4 #include <linux/sched.h>
5 #include <linux/errno.h>
9 #include <linux/config.h>
10 #include <linux/gfp.h>
11 #include <linux/list.h>
12 #include <linux/mmzone.h>
13 #include <linux/rbtree.h>
14 #include <linux/prio_tree.h>
20 #ifndef CONFIG_DISCONTIGMEM /* Don't use mapnrs, do it properly */
21 extern unsigned long max_mapnr;
24 extern unsigned long num_physpages;
25 extern void * high_memory;
26 extern unsigned long vmalloc_earlyreserve;
27 extern int page_cluster;
30 #include <asm/pgtable.h>
31 #include <asm/processor.h>
32 #include <asm/atomic.h>
35 #define MM_VM_SIZE(mm) TASK_SIZE
39 * Linux kernel virtual memory manager primitives.
40 * The idea being to have a "virtual" mm in the same way
41 * we have a virtual fs - giving a cleaner interface to the
42 * mm details, and allowing different kinds of memory mappings
43 * (from shared memory to executable loading to arbitrary
48 * This struct defines a memory VMM memory area. There is one of these
49 * per VM-area/task. A VM area is any part of the process virtual memory
50 * space that has a special rule for the page-fault handlers (ie a shared
51 * library, the executable area etc).
53 struct vm_area_struct {
54 struct mm_struct * vm_mm; /* The address space we belong to. */
55 unsigned long vm_start; /* Our start address within vm_mm. */
56 unsigned long vm_end; /* The first byte after our end address
59 /* linked list of VM areas per task, sorted by address */
60 struct vm_area_struct *vm_next;
62 pgprot_t vm_page_prot; /* Access permissions of this VMA. */
63 unsigned long vm_flags; /* Flags, listed below. */
68 * For areas with an address space and backing store,
69 * linkage into the address_space->i_mmap prio tree, or
70 * linkage to the list of like vmas hanging off its node, or
71 * linkage of vma in the address_space->i_mmap_nonlinear list.
75 struct list_head list;
76 void *parent; /* aligns with prio_tree_node parent */
77 struct vm_area_struct *head;
80 struct prio_tree_node prio_tree_node;
84 * A file's MAP_PRIVATE vma can be in both i_mmap tree and anon_vma
85 * list, after a COW of one of the file pages. A MAP_SHARED vma
86 * can only be in the i_mmap tree. An anonymous MAP_PRIVATE, stack
87 * or brk vma (with NULL file) can only be in an anon_vma list.
89 struct list_head anon_vma_node; /* Serialized by anon_vma->lock */
90 struct anon_vma *anon_vma; /* Serialized by page_table_lock */
92 /* Function pointers to deal with this struct. */
93 struct vm_operations_struct * vm_ops;
95 /* Information about our backing store: */
96 unsigned long vm_pgoff; /* Offset (within vm_file) in PAGE_SIZE
97 units, *not* PAGE_CACHE_SIZE */
98 struct file * vm_file; /* File we map to (can be NULL). */
99 void * vm_private_data; /* was vm_pte (shared mem) */
102 struct mempolicy *vm_policy; /* NUMA policy for the VMA */
109 #define VM_READ 0x00000001 /* currently active flags */
110 #define VM_WRITE 0x00000002
111 #define VM_EXEC 0x00000004
112 #define VM_SHARED 0x00000008
114 #define VM_MAYREAD 0x00000010 /* limits for mprotect() etc */
115 #define VM_MAYWRITE 0x00000020
116 #define VM_MAYEXEC 0x00000040
117 #define VM_MAYSHARE 0x00000080
119 #define VM_GROWSDOWN 0x00000100 /* general info on the segment */
120 #define VM_GROWSUP 0x00000200
121 #define VM_SHM 0x00000400 /* shared memory area, don't swap out */
122 #define VM_DENYWRITE 0x00000800 /* ETXTBSY on write attempts.. */
124 #define VM_EXECUTABLE 0x00001000
125 #define VM_LOCKED 0x00002000
126 #define VM_IO 0x00004000 /* Memory mapped I/O or similar */
128 /* Used by sys_madvise() */
129 #define VM_SEQ_READ 0x00008000 /* App will access data sequentially */
130 #define VM_RAND_READ 0x00010000 /* App will not benefit from clustered reads */
132 #define VM_DONTCOPY 0x00020000 /* Do not copy this vma on fork */
133 #define VM_DONTEXPAND 0x00040000 /* Cannot expand with mremap() */
134 #define VM_RESERVED 0x00080000 /* Don't unmap it from swap_out */
135 #define VM_ACCOUNT 0x00100000 /* Is a VM accounted object */
136 #define VM_HUGETLB 0x00400000 /* Huge TLB Page VM */
137 #define VM_NONLINEAR 0x00800000 /* Is non-linear (remap_file_pages) */
139 #ifndef VM_STACK_DEFAULT_FLAGS /* arch can override this */
140 #define VM_STACK_DEFAULT_FLAGS VM_DATA_DEFAULT_FLAGS
143 #ifdef CONFIG_STACK_GROWSUP
144 #define VM_STACK_FLAGS (VM_GROWSUP | VM_STACK_DEFAULT_FLAGS | VM_ACCOUNT)
146 #define VM_STACK_FLAGS (VM_GROWSDOWN | VM_STACK_DEFAULT_FLAGS | VM_ACCOUNT)
149 #define VM_READHINTMASK (VM_SEQ_READ | VM_RAND_READ)
150 #define VM_ClearReadHint(v) (v)->vm_flags &= ~VM_READHINTMASK
151 #define VM_NormalReadHint(v) (!((v)->vm_flags & VM_READHINTMASK))
152 #define VM_SequentialReadHint(v) ((v)->vm_flags & VM_SEQ_READ)
153 #define VM_RandomReadHint(v) ((v)->vm_flags & VM_RAND_READ)
156 * mapping from the currently active vm_flags protection bits (the
157 * low four bits) to a page protection mask..
159 extern pgprot_t protection_map[16];
163 * These are the virtual MM functions - opening of an area, closing and
164 * unmapping it (needed to keep files on disk up-to-date etc), pointer
165 * to the functions called when a no-page or a wp-page exception occurs.
167 struct vm_operations_struct {
168 void (*open)(struct vm_area_struct * area);
169 void (*close)(struct vm_area_struct * area);
170 struct page * (*nopage)(struct vm_area_struct * area, unsigned long address, int *type);
171 int (*populate)(struct vm_area_struct * area, unsigned long address, unsigned long len, pgprot_t prot, unsigned long pgoff, int nonblock);
173 int (*set_policy)(struct vm_area_struct *vma, struct mempolicy *new);
174 struct mempolicy *(*get_policy)(struct vm_area_struct *vma,
182 #ifdef ARCH_HAS_ATOMIC_UNSIGNED
183 typedef unsigned page_flags_t;
185 typedef unsigned long page_flags_t;
189 * Each physical page in the system has a struct page associated with
190 * it to keep track of whatever it is we are using the page for at the
191 * moment. Note that we have no way to track which tasks are using
195 page_flags_t flags; /* Atomic flags, some possibly
196 * updated asynchronously */
197 atomic_t _count; /* Usage count, see below. */
198 unsigned int mapcount; /* Count of ptes mapped in mms,
199 * to show when page is mapped
200 * & limit reverse map searches,
201 * protected by PG_maplock.
203 unsigned long private; /* Mapping-private opaque data:
204 * usually used for buffer_heads
205 * if PagePrivate set; used for
206 * swp_entry_t if PageSwapCache
208 struct address_space *mapping; /* If PG_anon clear, points to
209 * inode address_space, or NULL.
210 * If page mapped as anonymous
211 * memory, PG_anon is set, and
212 * it points to anon_vma object.
214 pgoff_t index; /* Our offset within mapping. */
215 struct list_head lru; /* Pageout list, eg. active_list
216 * protected by zone->lru_lock !
219 * On machines where all RAM is mapped into kernel address space,
220 * we can simply calculate the virtual address. On machines with
221 * highmem some memory is mapped into kernel virtual memory
222 * dynamically, so we need a place to store that address.
223 * Note that this field could be 16 bits on x86 ... ;)
225 * Architectures with slow multiplication can define
226 * WANT_PAGE_VIRTUAL in asm/page.h
228 #if defined(WANT_PAGE_VIRTUAL)
229 void *virtual; /* Kernel virtual address (NULL if
230 not kmapped, ie. highmem) */
231 #endif /* WANT_PAGE_VIRTUAL */
235 * FIXME: take this include out, include page-flags.h in
236 * files which need it (119 of them)
238 #include <linux/page-flags.h>
241 * Methods to modify the page usage count.
243 * What counts for a page usage:
244 * - cache mapping (page->mapping)
245 * - private data (page->private)
246 * - page mapped in a task's page tables, each mapping
247 * is counted separately
249 * Also, many kernel routines increase the page count before a critical
250 * routine so they can be sure the page doesn't go away from under them.
252 * Since 2.6.6 (approx), a free page has ->_count = -1. This is so that we
253 * can use atomic_add_negative(-1, page->_count) to detect when the page
254 * becomes free and so that we can also use atomic_inc_and_test to atomically
255 * detect when we just tried to grab a ref on a page which some other CPU has
256 * already deemed to be freeable.
258 * NO code should make assumptions about this internal detail! Use the provided
259 * macros which retain the old rules: page_count(page) == 0 is a free page.
263 * Drop a ref, return true if the logical refcount fell to zero (the page has
266 #define put_page_testzero(p) \
268 BUG_ON(page_count(p) == 0); \
269 atomic_add_negative(-1, &(p)->_count); \
273 * Grab a ref, return true if the page previously had a logical refcount of
274 * zero. ie: returns true if we just grabbed an already-deemed-to-be-free page
276 #define get_page_testone(p) atomic_inc_and_test(&(p)->_count)
278 #define set_page_count(p,v) atomic_set(&(p)->_count, v - 1)
279 #define __put_page(p) atomic_dec(&(p)->_count)
281 extern void FASTCALL(__page_cache_release(struct page *));
283 #ifdef CONFIG_HUGETLB_PAGE
285 static inline int page_count(struct page *p)
288 p = (struct page *)p->private;
289 return atomic_read(&(p)->_count) + 1;
292 static inline void get_page(struct page *page)
294 if (unlikely(PageCompound(page)))
295 page = (struct page *)page->private;
296 atomic_inc(&page->_count);
299 void put_page(struct page *page);
301 #else /* CONFIG_HUGETLB_PAGE */
303 #define page_count(p) (atomic_read(&(p)->_count) + 1)
305 static inline void get_page(struct page *page)
307 atomic_inc(&page->_count);
310 static inline void put_page(struct page *page)
312 if (!PageReserved(page) && put_page_testzero(page))
313 __page_cache_release(page);
316 #endif /* CONFIG_HUGETLB_PAGE */
319 * Multiple processes may "see" the same page. E.g. for untouched
320 * mappings of /dev/null, all processes see the same page full of
321 * zeroes, and text pages of executables and shared libraries have
322 * only one copy in memory, at most, normally.
324 * For the non-reserved pages, page_count(page) denotes a reference count.
325 * page_count() == 0 means the page is free.
326 * page_count() == 1 means the page is used for exactly one purpose
327 * (e.g. a private data page of one process).
329 * A page may be used for kmalloc() or anyone else who does a
330 * __get_free_page(). In this case the page_count() is at least 1, and
331 * all other fields are unused but should be 0 or NULL. The
332 * management of this page is the responsibility of the one who uses
335 * The other pages (we may call them "process pages") are completely
336 * managed by the Linux memory manager: I/O, buffers, swapping etc.
337 * The following discussion applies only to them.
339 * A page may belong to an inode's memory mapping. In this case,
340 * page->mapping is the pointer to the inode, and page->index is the
341 * file offset of the page, in units of PAGE_CACHE_SIZE.
343 * A page contains an opaque `private' member, which belongs to the
344 * page's address_space. Usually, this is the address of a circular
345 * list of the page's disk buffers.
347 * For pages belonging to inodes, the page_count() is the number of
348 * attaches, plus 1 if `private' contains something, plus one for
349 * the page cache itself.
351 * All pages belonging to an inode are in these doubly linked lists:
352 * mapping->clean_pages, mapping->dirty_pages and mapping->locked_pages;
353 * using the page->list list_head. These fields are also used for
354 * freelist managemet (when page_count()==0).
356 * There is also a per-mapping radix tree mapping index to the page
357 * in memory if present. The tree is rooted at mapping->root.
359 * All process pages can do I/O:
360 * - inode pages may need to be read from disk,
361 * - inode pages which have been modified and are MAP_SHARED may need
362 * to be written to disk,
363 * - private pages which have been modified may need to be swapped out
364 * to swap space and (later) to be read back into memory.
368 * The zone field is never updated after free_area_init_core()
369 * sets it, so none of the operations on it need to be atomic.
370 * We'll have up to (MAX_NUMNODES * MAX_NR_ZONES) zones total,
371 * so we use (MAX_NODES_SHIFT + MAX_ZONES_SHIFT) here to get enough bits.
373 #define NODEZONE_SHIFT (sizeof(page_flags_t)*8 - MAX_NODES_SHIFT - MAX_ZONES_SHIFT)
374 #define NODEZONE(node, zone) ((node << ZONES_SHIFT) | zone)
376 static inline unsigned long page_zonenum(struct page *page)
378 return (page->flags >> NODEZONE_SHIFT) & (~(~0UL << ZONES_SHIFT));
380 static inline unsigned long page_to_nid(struct page *page)
382 return (page->flags >> (NODEZONE_SHIFT + ZONES_SHIFT));
386 extern struct zone *zone_table[];
388 static inline struct zone *page_zone(struct page *page)
390 return zone_table[page->flags >> NODEZONE_SHIFT];
393 static inline void set_page_zone(struct page *page, unsigned long nodezone_num)
395 page->flags &= ~(~0UL << NODEZONE_SHIFT);
396 page->flags |= nodezone_num << NODEZONE_SHIFT;
399 #ifndef CONFIG_DISCONTIGMEM
400 /* The array of struct pages - for discontigmem use pgdat->lmem_map */
401 extern struct page *mem_map;
404 static inline void *lowmem_page_address(struct page *page)
406 return __va(page_to_pfn(page) << PAGE_SHIFT);
409 #if defined(CONFIG_HIGHMEM) && !defined(WANT_PAGE_VIRTUAL)
410 #define HASHED_PAGE_VIRTUAL
413 #if defined(WANT_PAGE_VIRTUAL)
414 #define page_address(page) ((page)->virtual)
415 #define set_page_address(page, address) \
417 (page)->virtual = (address); \
419 #define page_address_init() do { } while(0)
422 #if defined(HASHED_PAGE_VIRTUAL)
423 void *page_address(struct page *page);
424 void set_page_address(struct page *page, void *virtual);
425 void page_address_init(void);
428 #if !defined(HASHED_PAGE_VIRTUAL) && !defined(WANT_PAGE_VIRTUAL)
429 #define page_address(page) lowmem_page_address(page)
430 #define set_page_address(page, address) do { } while(0)
431 #define page_address_init() do { } while(0)
435 * On an anonymous page mapped into a user virtual memory area,
436 * page->mapping points to its anon_vma, not to a struct address_space.
438 * Please note that, confusingly, "page_mapping" refers to the inode
439 * address_space which maps the page from disk; whereas "page_mapped"
440 * refers to user virtual address space into which the page is mapped.
442 extern struct address_space swapper_space;
443 static inline struct address_space *page_mapping(struct page *page)
445 struct address_space *mapping = NULL;
447 if (unlikely(PageSwapCache(page)))
448 mapping = &swapper_space;
449 else if (likely(!PageAnon(page)))
450 mapping = page->mapping;
455 * Return the pagecache index of the passed page. Regular pagecache pages
456 * use ->index whereas swapcache pages use ->private
458 static inline pgoff_t page_index(struct page *page)
460 if (unlikely(PageSwapCache(page)))
461 return page->private;
466 * Return true if this page is mapped into pagetables.
468 static inline int page_mapped(struct page *page)
470 return page->mapcount != 0;
474 * Error return values for the *_nopage functions
476 #define NOPAGE_SIGBUS (NULL)
477 #define NOPAGE_OOM ((struct page *) (-1))
480 * Different kinds of faults, as returned by handle_mm_fault().
481 * Used to decide whether a process gets delivered SIGBUS or
482 * just gets major/minor fault counters bumped up.
484 #define VM_FAULT_OOM (-1)
485 #define VM_FAULT_SIGBUS 0
486 #define VM_FAULT_MINOR 1
487 #define VM_FAULT_MAJOR 2
489 #define offset_in_page(p) ((unsigned long)(p) & ~PAGE_MASK)
491 extern void show_free_areas(void);
493 struct page *shmem_nopage(struct vm_area_struct * vma,
494 unsigned long address, int *type);
495 int shmem_set_policy(struct vm_area_struct *vma, struct mempolicy *new);
496 struct mempolicy *shmem_get_policy(struct vm_area_struct *vma,
498 struct file *shmem_file_setup(char * name, loff_t size, unsigned long flags);
499 void shmem_lock(struct file * file, int lock);
500 int shmem_zero_setup(struct vm_area_struct *);
503 * Parameter block passed down to zap_pte_range in exceptional cases.
506 struct vm_area_struct *nonlinear_vma; /* Check page->index if set */
507 struct address_space *check_mapping; /* Check page->mapping if set */
508 pgoff_t first_index; /* Lowest page->index to unmap */
509 pgoff_t last_index; /* Highest page->index to unmap */
510 int atomic; /* May not schedule() */
513 void zap_page_range(struct vm_area_struct *vma, unsigned long address,
514 unsigned long size, struct zap_details *);
515 int unmap_vmas(struct mmu_gather **tlbp, struct mm_struct *mm,
516 struct vm_area_struct *start_vma, unsigned long start_addr,
517 unsigned long end_addr, unsigned long *nr_accounted,
518 struct zap_details *);
519 void clear_page_tables(struct mmu_gather *tlb, unsigned long first, int nr);
520 int copy_page_range(struct mm_struct *dst, struct mm_struct *src,
521 struct vm_area_struct *vma);
522 int zeromap_page_range(struct vm_area_struct *vma, unsigned long from,
523 unsigned long size, pgprot_t prot);
524 void unmap_mapping_range(struct address_space *mapping,
525 loff_t const holebegin, loff_t const holelen, int even_cows);
527 static inline void unmap_shared_mapping_range(struct address_space *mapping,
528 loff_t const holebegin, loff_t const holelen)
530 unmap_mapping_range(mapping, holebegin, holelen, 0);
533 extern int vmtruncate(struct inode * inode, loff_t offset);
534 extern pmd_t *FASTCALL(__pmd_alloc(struct mm_struct *mm, pgd_t *pgd, unsigned long address));
535 extern pte_t *FASTCALL(pte_alloc_kernel(struct mm_struct *mm, pmd_t *pmd, unsigned long address));
536 extern pte_t *FASTCALL(pte_alloc_map(struct mm_struct *mm, pmd_t *pmd, unsigned long address));
537 extern int install_page(struct mm_struct *mm, struct vm_area_struct *vma, unsigned long addr, struct page *page, pgprot_t prot);
538 extern int install_file_pte(struct mm_struct *mm, struct vm_area_struct *vma, unsigned long addr, unsigned long pgoff, pgprot_t prot);
539 extern int handle_mm_fault(struct mm_struct *mm,struct vm_area_struct *vma, unsigned long address, int write_access);
540 extern int make_pages_present(unsigned long addr, unsigned long end);
541 extern int access_process_vm(struct task_struct *tsk, unsigned long addr, void *buf, int len, int write);
542 void install_arg_page(struct vm_area_struct *, struct page *, unsigned long);
544 int get_user_pages(struct task_struct *tsk, struct mm_struct *mm, unsigned long start,
545 int len, int write, int force, struct page **pages, struct vm_area_struct **vmas);
547 int __set_page_dirty_buffers(struct page *page);
548 int __set_page_dirty_nobuffers(struct page *page);
549 int redirty_page_for_writepage(struct writeback_control *wbc,
551 int FASTCALL(set_page_dirty(struct page *page));
552 int set_page_dirty_lock(struct page *page);
553 int clear_page_dirty_for_io(struct page *page);
556 * Prototype to add a shrinker callback for ageable caches.
558 * These functions are passed a count `nr_to_scan' and a gfpmask. They should
559 * scan `nr_to_scan' objects, attempting to free them.
561 * The callback must the number of objects which remain in the cache.
563 * The callback will be passes nr_to_scan == 0 when the VM is querying the
564 * cache size, so a fastpath for that case is appropriate.
566 typedef int (*shrinker_t)(int nr_to_scan, unsigned int gfp_mask);
569 * Add an aging callback. The int is the number of 'seeks' it takes
570 * to recreate one of the objects that these functions age.
573 #define DEFAULT_SEEKS 2
575 extern struct shrinker *set_shrinker(int, shrinker_t);
576 extern void remove_shrinker(struct shrinker *shrinker);
579 * On a two-level page table, this ends up being trivial. Thus the
580 * inlining and the symmetry break with pte_alloc_map() that does all
581 * of this out-of-line.
583 static inline pmd_t *pmd_alloc(struct mm_struct *mm, pgd_t *pgd, unsigned long address)
586 return __pmd_alloc(mm, pgd, address);
587 return pmd_offset(pgd, address);
590 extern void free_area_init(unsigned long * zones_size);
591 extern void free_area_init_node(int nid, pg_data_t *pgdat, struct page *pmap,
592 unsigned long * zones_size, unsigned long zone_start_pfn,
593 unsigned long *zholes_size);
594 extern void memmap_init_zone(struct page *, unsigned long, int,
595 unsigned long, unsigned long);
596 extern void mem_init(void);
597 extern void show_mem(void);
598 extern void si_meminfo(struct sysinfo * val);
599 extern void si_meminfo_node(struct sysinfo *val, int nid);
601 static inline void vma_prio_tree_init(struct vm_area_struct *vma)
603 vma->shared.vm_set.list.next = NULL;
604 vma->shared.vm_set.list.prev = NULL;
605 vma->shared.vm_set.parent = NULL;
606 vma->shared.vm_set.head = NULL;
610 void vma_prio_tree_add(struct vm_area_struct *, struct vm_area_struct *old);
611 void vma_prio_tree_insert(struct vm_area_struct *, struct prio_tree_root *);
612 void vma_prio_tree_remove(struct vm_area_struct *, struct prio_tree_root *);
613 struct vm_area_struct *vma_prio_tree_next(
614 struct vm_area_struct *, struct prio_tree_root *,
615 struct prio_tree_iter *, pgoff_t begin, pgoff_t end);
618 extern void vma_adjust(struct vm_area_struct *vma, unsigned long start,
619 unsigned long end, pgoff_t pgoff, struct vm_area_struct *insert);
620 extern struct vm_area_struct *vma_merge(struct mm_struct *,
621 struct vm_area_struct *prev, unsigned long addr, unsigned long end,
622 unsigned long vm_flags, struct anon_vma *, struct file *, pgoff_t,
624 extern struct anon_vma *find_mergeable_anon_vma(struct vm_area_struct *);
625 extern int split_vma(struct mm_struct *,
626 struct vm_area_struct *, unsigned long addr, int new_below);
627 extern void insert_vm_struct(struct mm_struct *, struct vm_area_struct *);
628 extern void __vma_link_rb(struct mm_struct *, struct vm_area_struct *,
629 struct rb_node **, struct rb_node *);
630 extern struct vm_area_struct *copy_vma(struct vm_area_struct **,
631 unsigned long addr, unsigned long len, pgoff_t pgoff);
632 extern void exit_mmap(struct mm_struct *);
634 extern unsigned long get_unmapped_area(struct file *, unsigned long, unsigned long, unsigned long, unsigned long);
636 extern unsigned long do_mmap_pgoff(struct file *file, unsigned long addr,
637 unsigned long len, unsigned long prot,
638 unsigned long flag, unsigned long pgoff);
640 static inline unsigned long do_mmap(struct file *file, unsigned long addr,
641 unsigned long len, unsigned long prot,
642 unsigned long flag, unsigned long offset)
644 unsigned long ret = -EINVAL;
645 if ((offset + PAGE_ALIGN(len)) < offset)
647 if (!(offset & ~PAGE_MASK))
648 ret = do_mmap_pgoff(file, addr, len, prot, flag, offset >> PAGE_SHIFT);
653 extern int do_munmap(struct mm_struct *, unsigned long, size_t);
655 extern unsigned long do_brk(unsigned long, unsigned long);
658 extern unsigned long page_unuse(struct page *);
659 extern void truncate_inode_pages(struct address_space *, loff_t);
661 /* generic vm_area_ops exported for stackable file systems */
662 struct page *filemap_nopage(struct vm_area_struct *, unsigned long, int *);
664 /* mm/page-writeback.c */
665 int write_one_page(struct page *page, int wait);
668 #define VM_MAX_READAHEAD 128 /* kbytes */
669 #define VM_MIN_READAHEAD 16 /* kbytes (includes current page) */
671 int do_page_cache_readahead(struct address_space *mapping, struct file *filp,
672 unsigned long offset, unsigned long nr_to_read);
673 int force_page_cache_readahead(struct address_space *mapping, struct file *filp,
674 unsigned long offset, unsigned long nr_to_read);
675 void page_cache_readahead(struct address_space *mapping,
676 struct file_ra_state *ra,
678 unsigned long offset);
679 void handle_ra_miss(struct address_space *mapping,
680 struct file_ra_state *ra, pgoff_t offset);
681 unsigned long max_sane_readahead(unsigned long nr);
683 /* Do stack extension */
684 extern int expand_stack(struct vm_area_struct * vma, unsigned long address);
686 /* Look up the first VMA which satisfies addr < vm_end, NULL if none. */
687 extern struct vm_area_struct * find_vma(struct mm_struct * mm, unsigned long addr);
688 extern struct vm_area_struct * find_vma_prev(struct mm_struct * mm, unsigned long addr,
689 struct vm_area_struct **pprev);
691 /* Look up the first VMA which intersects the interval start_addr..end_addr-1,
692 NULL if none. Assume start_addr < end_addr. */
693 static inline struct vm_area_struct * find_vma_intersection(struct mm_struct * mm, unsigned long start_addr, unsigned long end_addr)
695 struct vm_area_struct * vma = find_vma(mm,start_addr);
697 if (vma && end_addr <= vma->vm_start)
702 static inline unsigned long vma_pages(struct vm_area_struct *vma)
704 return (vma->vm_end - vma->vm_start) >> PAGE_SHIFT;
707 extern struct vm_area_struct *find_extend_vma(struct mm_struct *mm, unsigned long addr);
709 extern struct page * vmalloc_to_page(void *addr);
710 extern struct page * follow_page(struct mm_struct *mm, unsigned long address,
712 extern int remap_page_range(struct vm_area_struct *vma, unsigned long from,
713 unsigned long to, unsigned long size, pgprot_t prot);
715 #ifndef CONFIG_DEBUG_PAGEALLOC
717 kernel_map_pages(struct page *page, int numpages, int enable)
722 #ifndef CONFIG_ARCH_GATE_AREA
723 extern struct vm_area_struct *get_gate_vma(struct task_struct *tsk);
724 int in_gate_area(struct task_struct *task, unsigned long addr);
727 #endif /* __KERNEL__ */
728 #endif /* _LINUX_MM_H */