blob: dbc2ca2057a54ff2c4a709de4b6e9a01694241bb [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * mm/rmap.c - physical to virtual reverse mappings
3 *
4 * Copyright 2001, Rik van Riel <riel@conectiva.com.br>
5 * Released under the General Public License (GPL).
6 *
7 * Simple, low overhead reverse mapping scheme.
8 * Please try to keep this thing as modular as possible.
9 *
10 * Provides methods for unmapping each kind of mapped page:
11 * the anon methods track anonymous pages, and
12 * the file methods track pages belonging to an inode.
13 *
14 * Original design by Rik van Riel <riel@conectiva.com.br> 2001
15 * File methods by Dave McCracken <dmccr@us.ibm.com> 2003, 2004
16 * Anonymous methods by Andrea Arcangeli <andrea@suse.de> 2004
17 * Contributions by Hugh Dickins <hugh@veritas.com> 2003, 2004
18 */
19
20/*
21 * Lock ordering in mm:
22 *
Jes Sorensen1b1dcc12006-01-09 15:59:24 -080023 * inode->i_mutex (while writing or truncating, not reading or faulting)
Nick Piggin82591e62006-10-19 23:29:10 -070024 * inode->i_alloc_sem (vmtruncate_range)
25 * mm->mmap_sem
26 * page->flags PG_locked (lock_page)
27 * mapping->i_mmap_lock
28 * anon_vma->lock
29 * mm->page_table_lock or pte_lock
30 * zone->lru_lock (in mark_page_accessed, isolate_lru_page)
31 * swap_lock (in swap_duplicate, swap_info_get)
32 * mmlist_lock (in mmput, drain_mmlist and others)
33 * mapping->private_lock (in __set_page_dirty_buffers)
34 * inode_lock (in set_page_dirty's __mark_inode_dirty)
35 * sb_lock (within inode_lock in fs/fs-writeback.c)
36 * mapping->tree_lock (widely used, in set_page_dirty,
37 * in arch-dependent flush_dcache_mmap_lock,
38 * within inode_lock in __sync_single_inode)
Nick Piggin7a405072007-10-16 23:26:02 -070039 * zone->lock (within radix tree node alloc)
Linus Torvalds1da177e2005-04-16 15:20:36 -070040 */
41
42#include <linux/mm.h>
43#include <linux/pagemap.h>
44#include <linux/swap.h>
45#include <linux/swapops.h>
46#include <linux/slab.h>
47#include <linux/init.h>
48#include <linux/rmap.h>
49#include <linux/rcupdate.h>
Christoph Lametera48d07a2006-02-01 03:05:38 -080050#include <linux/module.h>
Nick Piggin7de6b802006-12-22 01:09:33 -080051#include <linux/kallsyms.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070052
53#include <asm/tlbflush.h>
54
Pekka Enbergfcc234f2006-03-22 00:08:13 -080055struct kmem_cache *anon_vma_cachep;
Linus Torvalds1da177e2005-04-16 15:20:36 -070056
Linus Torvalds1da177e2005-04-16 15:20:36 -070057/* This must be called under the mmap_sem. */
58int anon_vma_prepare(struct vm_area_struct *vma)
59{
60 struct anon_vma *anon_vma = vma->anon_vma;
61
62 might_sleep();
63 if (unlikely(!anon_vma)) {
64 struct mm_struct *mm = vma->vm_mm;
65 struct anon_vma *allocated, *locked;
66
67 anon_vma = find_mergeable_anon_vma(vma);
68 if (anon_vma) {
69 allocated = NULL;
70 locked = anon_vma;
71 spin_lock(&locked->lock);
72 } else {
73 anon_vma = anon_vma_alloc();
74 if (unlikely(!anon_vma))
75 return -ENOMEM;
76 allocated = anon_vma;
77 locked = NULL;
78 }
79
80 /* page_table_lock to protect against threads */
81 spin_lock(&mm->page_table_lock);
82 if (likely(!vma->anon_vma)) {
83 vma->anon_vma = anon_vma;
Christoph Lameter06972122006-06-23 02:03:35 -070084 list_add_tail(&vma->anon_vma_node, &anon_vma->head);
Linus Torvalds1da177e2005-04-16 15:20:36 -070085 allocated = NULL;
86 }
87 spin_unlock(&mm->page_table_lock);
88
89 if (locked)
90 spin_unlock(&locked->lock);
91 if (unlikely(allocated))
92 anon_vma_free(allocated);
93 }
94 return 0;
95}
96
97void __anon_vma_merge(struct vm_area_struct *vma, struct vm_area_struct *next)
98{
99 BUG_ON(vma->anon_vma != next->anon_vma);
100 list_del(&next->anon_vma_node);
101}
102
103void __anon_vma_link(struct vm_area_struct *vma)
104{
105 struct anon_vma *anon_vma = vma->anon_vma;
106
Hugh Dickins30acbab2007-06-27 14:09:53 -0700107 if (anon_vma)
Christoph Lameter06972122006-06-23 02:03:35 -0700108 list_add_tail(&vma->anon_vma_node, &anon_vma->head);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700109}
110
111void anon_vma_link(struct vm_area_struct *vma)
112{
113 struct anon_vma *anon_vma = vma->anon_vma;
114
115 if (anon_vma) {
116 spin_lock(&anon_vma->lock);
Christoph Lameter06972122006-06-23 02:03:35 -0700117 list_add_tail(&vma->anon_vma_node, &anon_vma->head);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700118 spin_unlock(&anon_vma->lock);
119 }
120}
121
122void anon_vma_unlink(struct vm_area_struct *vma)
123{
124 struct anon_vma *anon_vma = vma->anon_vma;
125 int empty;
126
127 if (!anon_vma)
128 return;
129
130 spin_lock(&anon_vma->lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700131 list_del(&vma->anon_vma_node);
132
133 /* We must garbage collect the anon_vma if it's empty */
134 empty = list_empty(&anon_vma->head);
135 spin_unlock(&anon_vma->lock);
136
137 if (empty)
138 anon_vma_free(anon_vma);
139}
140
Christoph Lameter4ba9b9d2007-10-16 23:25:51 -0700141static void anon_vma_ctor(struct kmem_cache *cachep, void *data)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700142{
Christoph Lametera35afb82007-05-16 22:10:57 -0700143 struct anon_vma *anon_vma = data;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700144
Christoph Lametera35afb82007-05-16 22:10:57 -0700145 spin_lock_init(&anon_vma->lock);
146 INIT_LIST_HEAD(&anon_vma->head);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700147}
148
149void __init anon_vma_init(void)
150{
151 anon_vma_cachep = kmem_cache_create("anon_vma", sizeof(struct anon_vma),
Paul Mundt20c2df82007-07-20 10:11:58 +0900152 0, SLAB_DESTROY_BY_RCU|SLAB_PANIC, anon_vma_ctor);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700153}
154
155/*
156 * Getting a lock on a stable anon_vma from a page off the LRU is
157 * tricky: page_lock_anon_vma rely on RCU to guard against the races.
158 */
159static struct anon_vma *page_lock_anon_vma(struct page *page)
160{
Oleg Nesterov34bbd702007-02-28 20:13:49 -0800161 struct anon_vma *anon_vma;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700162 unsigned long anon_mapping;
163
164 rcu_read_lock();
165 anon_mapping = (unsigned long) page->mapping;
166 if (!(anon_mapping & PAGE_MAPPING_ANON))
167 goto out;
168 if (!page_mapped(page))
169 goto out;
170
171 anon_vma = (struct anon_vma *) (anon_mapping - PAGE_MAPPING_ANON);
172 spin_lock(&anon_vma->lock);
Oleg Nesterov34bbd702007-02-28 20:13:49 -0800173 return anon_vma;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700174out:
175 rcu_read_unlock();
Oleg Nesterov34bbd702007-02-28 20:13:49 -0800176 return NULL;
177}
178
179static void page_unlock_anon_vma(struct anon_vma *anon_vma)
180{
181 spin_unlock(&anon_vma->lock);
182 rcu_read_unlock();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700183}
184
185/*
Lee Schermerhorn3ad33b22007-11-14 16:59:10 -0800186 * At what user virtual address is page expected in @vma?
187 * Returns virtual address or -EFAULT if page's index/offset is not
188 * within the range mapped the @vma.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700189 */
190static inline unsigned long
191vma_address(struct page *page, struct vm_area_struct *vma)
192{
193 pgoff_t pgoff = page->index << (PAGE_CACHE_SHIFT - PAGE_SHIFT);
194 unsigned long address;
195
196 address = vma->vm_start + ((pgoff - vma->vm_pgoff) << PAGE_SHIFT);
197 if (unlikely(address < vma->vm_start || address >= vma->vm_end)) {
Lee Schermerhorn3ad33b22007-11-14 16:59:10 -0800198 /* page should be within @vma mapping range */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700199 return -EFAULT;
200 }
201 return address;
202}
203
204/*
205 * At what user virtual address is page expected in vma? checking that the
Hugh Dickinsee498ed2005-11-21 21:32:18 -0800206 * page matches the vma: currently only used on anon pages, by unuse_vma;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700207 */
208unsigned long page_address_in_vma(struct page *page, struct vm_area_struct *vma)
209{
210 if (PageAnon(page)) {
211 if ((void *)vma->anon_vma !=
212 (void *)page->mapping - PAGE_MAPPING_ANON)
213 return -EFAULT;
214 } else if (page->mapping && !(vma->vm_flags & VM_NONLINEAR)) {
Hugh Dickinsee498ed2005-11-21 21:32:18 -0800215 if (!vma->vm_file ||
216 vma->vm_file->f_mapping != page->mapping)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700217 return -EFAULT;
218 } else
219 return -EFAULT;
220 return vma_address(page, vma);
221}
222
223/*
Nikita Danilov81b40822005-05-01 08:58:36 -0700224 * Check that @page is mapped at @address into @mm.
225 *
Hugh Dickinsb8072f02005-10-29 18:16:41 -0700226 * On success returns with pte mapped and locked.
Nikita Danilov81b40822005-05-01 08:58:36 -0700227 */
Carsten Otteceffc072005-06-23 22:05:25 -0700228pte_t *page_check_address(struct page *page, struct mm_struct *mm,
Hugh Dickinsc0718802005-10-29 18:16:31 -0700229 unsigned long address, spinlock_t **ptlp)
Nikita Danilov81b40822005-05-01 08:58:36 -0700230{
231 pgd_t *pgd;
232 pud_t *pud;
233 pmd_t *pmd;
234 pte_t *pte;
Hugh Dickinsc0718802005-10-29 18:16:31 -0700235 spinlock_t *ptl;
Nikita Danilov81b40822005-05-01 08:58:36 -0700236
Nikita Danilov81b40822005-05-01 08:58:36 -0700237 pgd = pgd_offset(mm, address);
Hugh Dickinsc0718802005-10-29 18:16:31 -0700238 if (!pgd_present(*pgd))
239 return NULL;
240
241 pud = pud_offset(pgd, address);
242 if (!pud_present(*pud))
243 return NULL;
244
245 pmd = pmd_offset(pud, address);
246 if (!pmd_present(*pmd))
247 return NULL;
248
249 pte = pte_offset_map(pmd, address);
250 /* Make a quick check before getting the lock */
251 if (!pte_present(*pte)) {
252 pte_unmap(pte);
253 return NULL;
Nikita Danilov81b40822005-05-01 08:58:36 -0700254 }
Hugh Dickinsc0718802005-10-29 18:16:31 -0700255
Hugh Dickins4c21e2f2005-10-29 18:16:40 -0700256 ptl = pte_lockptr(mm, pmd);
Hugh Dickinsc0718802005-10-29 18:16:31 -0700257 spin_lock(ptl);
258 if (pte_present(*pte) && page_to_pfn(page) == pte_pfn(*pte)) {
259 *ptlp = ptl;
260 return pte;
261 }
262 pte_unmap_unlock(pte, ptl);
263 return NULL;
Nikita Danilov81b40822005-05-01 08:58:36 -0700264}
265
266/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700267 * Subfunctions of page_referenced: page_referenced_one called
268 * repeatedly from either page_referenced_anon or page_referenced_file.
269 */
270static int page_referenced_one(struct page *page,
Rik van Rielf7b7fd82005-11-28 13:44:07 -0800271 struct vm_area_struct *vma, unsigned int *mapcount)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700272{
273 struct mm_struct *mm = vma->vm_mm;
274 unsigned long address;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700275 pte_t *pte;
Hugh Dickinsc0718802005-10-29 18:16:31 -0700276 spinlock_t *ptl;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700277 int referenced = 0;
278
Linus Torvalds1da177e2005-04-16 15:20:36 -0700279 address = vma_address(page, vma);
280 if (address == -EFAULT)
281 goto out;
282
Hugh Dickinsc0718802005-10-29 18:16:31 -0700283 pte = page_check_address(page, mm, address, &ptl);
284 if (!pte)
285 goto out;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700286
Hugh Dickinsc0718802005-10-29 18:16:31 -0700287 if (ptep_clear_flush_young(vma, address, pte))
288 referenced++;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700289
Hugh Dickinsc0718802005-10-29 18:16:31 -0700290 /* Pretend the page is referenced if the task has the
291 swap token and is in the middle of a page fault. */
Rik van Rielf7b7fd82005-11-28 13:44:07 -0800292 if (mm != current->mm && has_swap_token(mm) &&
Hugh Dickinsc0718802005-10-29 18:16:31 -0700293 rwsem_is_locked(&mm->mmap_sem))
294 referenced++;
295
296 (*mapcount)--;
297 pte_unmap_unlock(pte, ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700298out:
299 return referenced;
300}
301
Rik van Rielf7b7fd82005-11-28 13:44:07 -0800302static int page_referenced_anon(struct page *page)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700303{
304 unsigned int mapcount;
305 struct anon_vma *anon_vma;
306 struct vm_area_struct *vma;
307 int referenced = 0;
308
309 anon_vma = page_lock_anon_vma(page);
310 if (!anon_vma)
311 return referenced;
312
313 mapcount = page_mapcount(page);
314 list_for_each_entry(vma, &anon_vma->head, anon_vma_node) {
Rik van Rielf7b7fd82005-11-28 13:44:07 -0800315 referenced += page_referenced_one(page, vma, &mapcount);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700316 if (!mapcount)
317 break;
318 }
Oleg Nesterov34bbd702007-02-28 20:13:49 -0800319
320 page_unlock_anon_vma(anon_vma);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700321 return referenced;
322}
323
324/**
325 * page_referenced_file - referenced check for object-based rmap
326 * @page: the page we're checking references on.
327 *
328 * For an object-based mapped page, find all the places it is mapped and
329 * check/clear the referenced flag. This is done by following the page->mapping
330 * pointer, then walking the chain of vmas it holds. It returns the number
331 * of references it found.
332 *
333 * This function is only called from page_referenced for object-based pages.
334 */
Rik van Rielf7b7fd82005-11-28 13:44:07 -0800335static int page_referenced_file(struct page *page)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700336{
337 unsigned int mapcount;
338 struct address_space *mapping = page->mapping;
339 pgoff_t pgoff = page->index << (PAGE_CACHE_SHIFT - PAGE_SHIFT);
340 struct vm_area_struct *vma;
341 struct prio_tree_iter iter;
342 int referenced = 0;
343
344 /*
345 * The caller's checks on page->mapping and !PageAnon have made
346 * sure that this is a file page: the check for page->mapping
347 * excludes the case just before it gets set on an anon page.
348 */
349 BUG_ON(PageAnon(page));
350
351 /*
352 * The page lock not only makes sure that page->mapping cannot
353 * suddenly be NULLified by truncation, it makes sure that the
354 * structure at mapping cannot be freed and reused yet,
355 * so we can safely take mapping->i_mmap_lock.
356 */
357 BUG_ON(!PageLocked(page));
358
359 spin_lock(&mapping->i_mmap_lock);
360
361 /*
362 * i_mmap_lock does not stabilize mapcount at all, but mapcount
363 * is more likely to be accurate if we note it after spinning.
364 */
365 mapcount = page_mapcount(page);
366
367 vma_prio_tree_foreach(vma, &iter, &mapping->i_mmap, pgoff, pgoff) {
368 if ((vma->vm_flags & (VM_LOCKED|VM_MAYSHARE))
369 == (VM_LOCKED|VM_MAYSHARE)) {
370 referenced++;
371 break;
372 }
Rik van Rielf7b7fd82005-11-28 13:44:07 -0800373 referenced += page_referenced_one(page, vma, &mapcount);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700374 if (!mapcount)
375 break;
376 }
377
378 spin_unlock(&mapping->i_mmap_lock);
379 return referenced;
380}
381
382/**
383 * page_referenced - test if the page was referenced
384 * @page: the page to test
385 * @is_locked: caller holds lock on the page
386 *
387 * Quick test_and_clear_referenced for all mappings to a page,
388 * returns the number of ptes which referenced the page.
389 */
Rik van Rielf7b7fd82005-11-28 13:44:07 -0800390int page_referenced(struct page *page, int is_locked)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700391{
392 int referenced = 0;
393
Linus Torvalds1da177e2005-04-16 15:20:36 -0700394 if (page_test_and_clear_young(page))
395 referenced++;
396
397 if (TestClearPageReferenced(page))
398 referenced++;
399
400 if (page_mapped(page) && page->mapping) {
401 if (PageAnon(page))
Rik van Rielf7b7fd82005-11-28 13:44:07 -0800402 referenced += page_referenced_anon(page);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700403 else if (is_locked)
Rik van Rielf7b7fd82005-11-28 13:44:07 -0800404 referenced += page_referenced_file(page);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700405 else if (TestSetPageLocked(page))
406 referenced++;
407 else {
408 if (page->mapping)
Rik van Rielf7b7fd82005-11-28 13:44:07 -0800409 referenced += page_referenced_file(page);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700410 unlock_page(page);
411 }
412 }
413 return referenced;
414}
415
Peter Zijlstrad08b3852006-09-25 23:30:57 -0700416static int page_mkclean_one(struct page *page, struct vm_area_struct *vma)
417{
418 struct mm_struct *mm = vma->vm_mm;
419 unsigned long address;
Peter Zijlstrac2fda5f2006-12-22 14:25:52 +0100420 pte_t *pte;
Peter Zijlstrad08b3852006-09-25 23:30:57 -0700421 spinlock_t *ptl;
422 int ret = 0;
423
424 address = vma_address(page, vma);
425 if (address == -EFAULT)
426 goto out;
427
428 pte = page_check_address(page, mm, address, &ptl);
429 if (!pte)
430 goto out;
431
Peter Zijlstrac2fda5f2006-12-22 14:25:52 +0100432 if (pte_dirty(*pte) || pte_write(*pte)) {
433 pte_t entry;
Peter Zijlstrad08b3852006-09-25 23:30:57 -0700434
Peter Zijlstrac2fda5f2006-12-22 14:25:52 +0100435 flush_cache_page(vma, address, pte_pfn(*pte));
436 entry = ptep_clear_flush(vma, address, pte);
437 entry = pte_wrprotect(entry);
438 entry = pte_mkclean(entry);
Al Virod6e88e62006-12-29 16:48:35 -0800439 set_pte_at(mm, address, pte, entry);
Peter Zijlstrac2fda5f2006-12-22 14:25:52 +0100440 ret = 1;
441 }
Peter Zijlstrad08b3852006-09-25 23:30:57 -0700442
Peter Zijlstrad08b3852006-09-25 23:30:57 -0700443 pte_unmap_unlock(pte, ptl);
444out:
445 return ret;
446}
447
448static int page_mkclean_file(struct address_space *mapping, struct page *page)
449{
450 pgoff_t pgoff = page->index << (PAGE_CACHE_SHIFT - PAGE_SHIFT);
451 struct vm_area_struct *vma;
452 struct prio_tree_iter iter;
453 int ret = 0;
454
455 BUG_ON(PageAnon(page));
456
457 spin_lock(&mapping->i_mmap_lock);
458 vma_prio_tree_foreach(vma, &iter, &mapping->i_mmap, pgoff, pgoff) {
459 if (vma->vm_flags & VM_SHARED)
460 ret += page_mkclean_one(page, vma);
461 }
462 spin_unlock(&mapping->i_mmap_lock);
463 return ret;
464}
465
466int page_mkclean(struct page *page)
467{
468 int ret = 0;
469
470 BUG_ON(!PageLocked(page));
471
472 if (page_mapped(page)) {
473 struct address_space *mapping = page_mapping(page);
Christian Borntraegerce7e9fa2007-11-20 11:13:36 +0100474 if (mapping) {
Peter Zijlstrad08b3852006-09-25 23:30:57 -0700475 ret = page_mkclean_file(mapping, page);
Christian Borntraegerce7e9fa2007-11-20 11:13:36 +0100476 if (page_test_dirty(page)) {
477 page_clear_dirty(page);
478 ret = 1;
479 }
Martin Schwidefsky6c210482007-04-27 16:01:57 +0200480 }
Peter Zijlstrad08b3852006-09-25 23:30:57 -0700481 }
482
483 return ret;
484}
Jaya Kumar60b59be2007-05-08 00:37:37 -0700485EXPORT_SYMBOL_GPL(page_mkclean);
Peter Zijlstrad08b3852006-09-25 23:30:57 -0700486
Linus Torvalds1da177e2005-04-16 15:20:36 -0700487/**
Nick Piggin9617d952006-01-06 00:11:12 -0800488 * page_set_anon_rmap - setup new anonymous rmap
489 * @page: the page to add the mapping to
490 * @vma: the vm area in which the mapping is added
491 * @address: the user virtual address mapped
492 */
493static void __page_set_anon_rmap(struct page *page,
494 struct vm_area_struct *vma, unsigned long address)
495{
496 struct anon_vma *anon_vma = vma->anon_vma;
497
498 BUG_ON(!anon_vma);
499 anon_vma = (void *) anon_vma + PAGE_MAPPING_ANON;
500 page->mapping = (struct address_space *) anon_vma;
501
502 page->index = linear_page_index(vma, address);
503
Nick Piggina74609f2006-01-06 00:11:20 -0800504 /*
505 * nr_mapped state can be updated without turning off
506 * interrupts because it is not modified via interrupt.
507 */
Christoph Lameterf3dbd342006-06-30 01:55:36 -0700508 __inc_zone_page_state(page, NR_ANON_PAGES);
Nick Piggin9617d952006-01-06 00:11:12 -0800509}
510
511/**
Nick Pigginc97a9e12007-05-16 22:11:21 -0700512 * page_set_anon_rmap - sanity check anonymous rmap addition
513 * @page: the page to add the mapping to
514 * @vma: the vm area in which the mapping is added
515 * @address: the user virtual address mapped
516 */
517static void __page_check_anon_rmap(struct page *page,
518 struct vm_area_struct *vma, unsigned long address)
519{
520#ifdef CONFIG_DEBUG_VM
521 /*
522 * The page's anon-rmap details (mapping and index) are guaranteed to
523 * be set up correctly at this point.
524 *
525 * We have exclusion against page_add_anon_rmap because the caller
526 * always holds the page locked, except if called from page_dup_rmap,
527 * in which case the page is already known to be setup.
528 *
529 * We have exclusion against page_add_new_anon_rmap because those pages
530 * are initially only visible via the pagetables, and the pte is locked
531 * over the call to page_add_new_anon_rmap.
532 */
533 struct anon_vma *anon_vma = vma->anon_vma;
534 anon_vma = (void *) anon_vma + PAGE_MAPPING_ANON;
535 BUG_ON(page->mapping != (struct address_space *)anon_vma);
536 BUG_ON(page->index != linear_page_index(vma, address));
537#endif
538}
539
540/**
Linus Torvalds1da177e2005-04-16 15:20:36 -0700541 * page_add_anon_rmap - add pte mapping to an anonymous page
542 * @page: the page to add the mapping to
543 * @vma: the vm area in which the mapping is added
544 * @address: the user virtual address mapped
545 *
Nick Pigginc97a9e12007-05-16 22:11:21 -0700546 * The caller needs to hold the pte lock and the page must be locked.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700547 */
548void page_add_anon_rmap(struct page *page,
549 struct vm_area_struct *vma, unsigned long address)
550{
Nick Pigginc97a9e12007-05-16 22:11:21 -0700551 VM_BUG_ON(!PageLocked(page));
552 VM_BUG_ON(address < vma->vm_start || address >= vma->vm_end);
Nick Piggin9617d952006-01-06 00:11:12 -0800553 if (atomic_inc_and_test(&page->_mapcount))
554 __page_set_anon_rmap(page, vma, address);
Nick Pigginc97a9e12007-05-16 22:11:21 -0700555 else
556 __page_check_anon_rmap(page, vma, address);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700557}
558
Nick Piggin9617d952006-01-06 00:11:12 -0800559/*
560 * page_add_new_anon_rmap - add pte mapping to a new anonymous page
561 * @page: the page to add the mapping to
562 * @vma: the vm area in which the mapping is added
563 * @address: the user virtual address mapped
564 *
565 * Same as page_add_anon_rmap but must only be called on *new* pages.
566 * This means the inc-and-test can be bypassed.
Nick Pigginc97a9e12007-05-16 22:11:21 -0700567 * Page does not have to be locked.
Nick Piggin9617d952006-01-06 00:11:12 -0800568 */
569void page_add_new_anon_rmap(struct page *page,
570 struct vm_area_struct *vma, unsigned long address)
571{
Nick Pigginc97a9e12007-05-16 22:11:21 -0700572 BUG_ON(address < vma->vm_start || address >= vma->vm_end);
Nick Piggin9617d952006-01-06 00:11:12 -0800573 atomic_set(&page->_mapcount, 0); /* elevate count by 1 (starts at -1) */
574 __page_set_anon_rmap(page, vma, address);
575}
576
Linus Torvalds1da177e2005-04-16 15:20:36 -0700577/**
578 * page_add_file_rmap - add pte mapping to a file page
579 * @page: the page to add the mapping to
580 *
Hugh Dickinsb8072f02005-10-29 18:16:41 -0700581 * The caller needs to hold the pte lock.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700582 */
583void page_add_file_rmap(struct page *page)
584{
Linus Torvalds1da177e2005-04-16 15:20:36 -0700585 if (atomic_inc_and_test(&page->_mapcount))
Christoph Lameter65ba55f2006-06-30 01:55:34 -0700586 __inc_zone_page_state(page, NR_FILE_MAPPED);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700587}
588
Nick Pigginc97a9e12007-05-16 22:11:21 -0700589#ifdef CONFIG_DEBUG_VM
590/**
591 * page_dup_rmap - duplicate pte mapping to a page
592 * @page: the page to add the mapping to
593 *
594 * For copy_page_range only: minimal extract from page_add_file_rmap /
595 * page_add_anon_rmap, avoiding unnecessary tests (already checked) so it's
596 * quicker.
597 *
598 * The caller needs to hold the pte lock.
599 */
600void page_dup_rmap(struct page *page, struct vm_area_struct *vma, unsigned long address)
601{
602 BUG_ON(page_mapcount(page) == 0);
603 if (PageAnon(page))
604 __page_check_anon_rmap(page, vma, address);
605 atomic_inc(&page->_mapcount);
606}
607#endif
608
Linus Torvalds1da177e2005-04-16 15:20:36 -0700609/**
610 * page_remove_rmap - take down pte mapping from a page
611 * @page: page to remove mapping from
612 *
Hugh Dickinsb8072f02005-10-29 18:16:41 -0700613 * The caller needs to hold the pte lock.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700614 */
Nick Piggin7de6b802006-12-22 01:09:33 -0800615void page_remove_rmap(struct page *page, struct vm_area_struct *vma)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700616{
Linus Torvalds1da177e2005-04-16 15:20:36 -0700617 if (atomic_add_negative(-1, &page->_mapcount)) {
Nick Pigginb7ab7952006-03-22 00:08:42 -0800618 if (unlikely(page_mapcount(page) < 0)) {
Dave Jonesef2bf0d2006-01-08 01:01:00 -0800619 printk (KERN_EMERG "Eeek! page_mapcount(page) went negative! (%d)\n", page_mapcount(page));
Nick Piggin7de6b802006-12-22 01:09:33 -0800620 printk (KERN_EMERG " page pfn = %lx\n", page_to_pfn(page));
Dave Jonesef2bf0d2006-01-08 01:01:00 -0800621 printk (KERN_EMERG " page->flags = %lx\n", page->flags);
622 printk (KERN_EMERG " page->count = %x\n", page_count(page));
623 printk (KERN_EMERG " page->mapping = %p\n", page->mapping);
Nick Piggin7de6b802006-12-22 01:09:33 -0800624 print_symbol (KERN_EMERG " vma->vm_ops = %s\n", (unsigned long)vma->vm_ops);
Nick Piggin54cb8822007-07-19 01:46:59 -0700625 if (vma->vm_ops) {
Nick Piggin7de6b802006-12-22 01:09:33 -0800626 print_symbol (KERN_EMERG " vma->vm_ops->nopage = %s\n", (unsigned long)vma->vm_ops->nopage);
Nick Piggin54cb8822007-07-19 01:46:59 -0700627 print_symbol (KERN_EMERG " vma->vm_ops->fault = %s\n", (unsigned long)vma->vm_ops->fault);
628 }
Nick Piggin7de6b802006-12-22 01:09:33 -0800629 if (vma->vm_file && vma->vm_file->f_op)
630 print_symbol (KERN_EMERG " vma->vm_file->f_op->mmap = %s\n", (unsigned long)vma->vm_file->f_op->mmap);
Dave Jonesb16bc642006-10-11 01:21:27 -0700631 BUG();
Dave Jonesef2bf0d2006-01-08 01:01:00 -0800632 }
Dave Jonesb16bc642006-10-11 01:21:27 -0700633
Linus Torvalds1da177e2005-04-16 15:20:36 -0700634 /*
635 * It would be tidy to reset the PageAnon mapping here,
636 * but that might overwrite a racing page_add_anon_rmap
637 * which increments mapcount after us but sets mapping
638 * before us: so leave the reset to free_hot_cold_page,
639 * and remember that it's only reliable while mapped.
640 * Leaving it set also helps swapoff to reinstate ptes
641 * faster for those pages still in swapcache.
642 */
Martin Schwidefsky6c210482007-04-27 16:01:57 +0200643 if (page_test_dirty(page)) {
644 page_clear_dirty(page);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700645 set_page_dirty(page);
Martin Schwidefsky6c210482007-04-27 16:01:57 +0200646 }
Christoph Lameterf3dbd342006-06-30 01:55:36 -0700647 __dec_zone_page_state(page,
648 PageAnon(page) ? NR_ANON_PAGES : NR_FILE_MAPPED);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700649 }
650}
651
652/*
653 * Subfunctions of try_to_unmap: try_to_unmap_one called
654 * repeatedly from either try_to_unmap_anon or try_to_unmap_file.
655 */
Christoph Lametera48d07a2006-02-01 03:05:38 -0800656static int try_to_unmap_one(struct page *page, struct vm_area_struct *vma,
Christoph Lameter73523492006-06-23 02:03:27 -0700657 int migration)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700658{
659 struct mm_struct *mm = vma->vm_mm;
660 unsigned long address;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700661 pte_t *pte;
662 pte_t pteval;
Hugh Dickinsc0718802005-10-29 18:16:31 -0700663 spinlock_t *ptl;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700664 int ret = SWAP_AGAIN;
665
Linus Torvalds1da177e2005-04-16 15:20:36 -0700666 address = vma_address(page, vma);
667 if (address == -EFAULT)
668 goto out;
669
Hugh Dickinsc0718802005-10-29 18:16:31 -0700670 pte = page_check_address(page, mm, address, &ptl);
671 if (!pte)
Nikita Danilov81b40822005-05-01 08:58:36 -0700672 goto out;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700673
674 /*
675 * If the page is mlock()d, we cannot swap it out.
676 * If it's recently referenced (perhaps page_referenced
677 * skipped over this mm) then we should reactivate it.
678 */
Christoph Lametere6a15302006-06-25 05:46:49 -0700679 if (!migration && ((vma->vm_flags & VM_LOCKED) ||
680 (ptep_clear_flush_young(vma, address, pte)))) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700681 ret = SWAP_FAIL;
682 goto out_unmap;
683 }
684
Linus Torvalds1da177e2005-04-16 15:20:36 -0700685 /* Nuke the page table entry. */
686 flush_cache_page(vma, address, page_to_pfn(page));
687 pteval = ptep_clear_flush(vma, address, pte);
688
689 /* Move the dirty bit to the physical page now the pte is gone. */
690 if (pte_dirty(pteval))
691 set_page_dirty(page);
692
Hugh Dickins365e9c872005-10-29 18:16:18 -0700693 /* Update high watermark before we lower rss */
694 update_hiwater_rss(mm);
695
Linus Torvalds1da177e2005-04-16 15:20:36 -0700696 if (PageAnon(page)) {
Hugh Dickins4c21e2f2005-10-29 18:16:40 -0700697 swp_entry_t entry = { .val = page_private(page) };
Christoph Lameter06972122006-06-23 02:03:35 -0700698
699 if (PageSwapCache(page)) {
700 /*
701 * Store the swap location in the pte.
702 * See handle_pte_fault() ...
703 */
704 swap_duplicate(entry);
705 if (list_empty(&mm->mmlist)) {
706 spin_lock(&mmlist_lock);
707 if (list_empty(&mm->mmlist))
708 list_add(&mm->mmlist, &init_mm.mmlist);
709 spin_unlock(&mmlist_lock);
710 }
Christoph Lameter442c9132006-06-23 02:03:38 -0700711 dec_mm_counter(mm, anon_rss);
Christoph Lameter04e62a22006-06-23 02:03:38 -0700712#ifdef CONFIG_MIGRATION
Christoph Lameter06972122006-06-23 02:03:35 -0700713 } else {
714 /*
715 * Store the pfn of the page in a special migration
716 * pte. do_swap_page() will wait until the migration
717 * pte is removed and then restart fault handling.
718 */
719 BUG_ON(!migration);
720 entry = make_migration_entry(page, pte_write(pteval));
Christoph Lameter04e62a22006-06-23 02:03:38 -0700721#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -0700722 }
723 set_pte_at(mm, address, pte, swp_entry_to_pte(entry));
724 BUG_ON(pte_file(*pte));
Hugh Dickins42946212005-10-29 18:16:05 -0700725 } else
Christoph Lameter04e62a22006-06-23 02:03:38 -0700726#ifdef CONFIG_MIGRATION
727 if (migration) {
728 /* Establish migration entry for a file page */
729 swp_entry_t entry;
730 entry = make_migration_entry(page, pte_write(pteval));
731 set_pte_at(mm, address, pte, swp_entry_to_pte(entry));
732 } else
733#endif
Hugh Dickins42946212005-10-29 18:16:05 -0700734 dec_mm_counter(mm, file_rss);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700735
Christoph Lameter04e62a22006-06-23 02:03:38 -0700736
Nick Piggin7de6b802006-12-22 01:09:33 -0800737 page_remove_rmap(page, vma);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700738 page_cache_release(page);
739
740out_unmap:
Hugh Dickinsc0718802005-10-29 18:16:31 -0700741 pte_unmap_unlock(pte, ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700742out:
743 return ret;
744}
745
746/*
747 * objrmap doesn't work for nonlinear VMAs because the assumption that
748 * offset-into-file correlates with offset-into-virtual-addresses does not hold.
749 * Consequently, given a particular page and its ->index, we cannot locate the
750 * ptes which are mapping that page without an exhaustive linear search.
751 *
752 * So what this code does is a mini "virtual scan" of each nonlinear VMA which
753 * maps the file to which the target page belongs. The ->vm_private_data field
754 * holds the current cursor into that scan. Successive searches will circulate
755 * around the vma's virtual address space.
756 *
757 * So as more replacement pressure is applied to the pages in a nonlinear VMA,
758 * more scanning pressure is placed against them as well. Eventually pages
759 * will become fully unmapped and are eligible for eviction.
760 *
761 * For very sparsely populated VMAs this is a little inefficient - chances are
762 * there there won't be many ptes located within the scan cluster. In this case
763 * maybe we could scan further - to the end of the pte page, perhaps.
764 */
765#define CLUSTER_SIZE min(32*PAGE_SIZE, PMD_SIZE)
766#define CLUSTER_MASK (~(CLUSTER_SIZE - 1))
767
768static void try_to_unmap_cluster(unsigned long cursor,
769 unsigned int *mapcount, struct vm_area_struct *vma)
770{
771 struct mm_struct *mm = vma->vm_mm;
772 pgd_t *pgd;
773 pud_t *pud;
774 pmd_t *pmd;
Hugh Dickinsc0718802005-10-29 18:16:31 -0700775 pte_t *pte;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700776 pte_t pteval;
Hugh Dickinsc0718802005-10-29 18:16:31 -0700777 spinlock_t *ptl;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700778 struct page *page;
779 unsigned long address;
780 unsigned long end;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700781
Linus Torvalds1da177e2005-04-16 15:20:36 -0700782 address = (vma->vm_start + cursor) & CLUSTER_MASK;
783 end = address + CLUSTER_SIZE;
784 if (address < vma->vm_start)
785 address = vma->vm_start;
786 if (end > vma->vm_end)
787 end = vma->vm_end;
788
789 pgd = pgd_offset(mm, address);
790 if (!pgd_present(*pgd))
Hugh Dickinsc0718802005-10-29 18:16:31 -0700791 return;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700792
793 pud = pud_offset(pgd, address);
794 if (!pud_present(*pud))
Hugh Dickinsc0718802005-10-29 18:16:31 -0700795 return;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700796
797 pmd = pmd_offset(pud, address);
798 if (!pmd_present(*pmd))
Hugh Dickinsc0718802005-10-29 18:16:31 -0700799 return;
800
801 pte = pte_offset_map_lock(mm, pmd, address, &ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700802
Hugh Dickins365e9c872005-10-29 18:16:18 -0700803 /* Update high watermark before we lower rss */
804 update_hiwater_rss(mm);
805
Hugh Dickinsc0718802005-10-29 18:16:31 -0700806 for (; address < end; pte++, address += PAGE_SIZE) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700807 if (!pte_present(*pte))
808 continue;
Linus Torvalds6aab3412005-11-28 14:34:23 -0800809 page = vm_normal_page(vma, address, *pte);
810 BUG_ON(!page || PageAnon(page));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700811
812 if (ptep_clear_flush_young(vma, address, pte))
813 continue;
814
815 /* Nuke the page table entry. */
Ben Collinseca35132005-11-29 11:45:26 -0800816 flush_cache_page(vma, address, pte_pfn(*pte));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700817 pteval = ptep_clear_flush(vma, address, pte);
818
819 /* If nonlinear, store the file page offset in the pte. */
820 if (page->index != linear_page_index(vma, address))
821 set_pte_at(mm, address, pte, pgoff_to_pte(page->index));
822
823 /* Move the dirty bit to the physical page now the pte is gone. */
824 if (pte_dirty(pteval))
825 set_page_dirty(page);
826
Nick Piggin7de6b802006-12-22 01:09:33 -0800827 page_remove_rmap(page, vma);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700828 page_cache_release(page);
Hugh Dickins42946212005-10-29 18:16:05 -0700829 dec_mm_counter(mm, file_rss);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700830 (*mapcount)--;
831 }
Hugh Dickinsc0718802005-10-29 18:16:31 -0700832 pte_unmap_unlock(pte - 1, ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700833}
834
Christoph Lameter73523492006-06-23 02:03:27 -0700835static int try_to_unmap_anon(struct page *page, int migration)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700836{
837 struct anon_vma *anon_vma;
838 struct vm_area_struct *vma;
839 int ret = SWAP_AGAIN;
840
841 anon_vma = page_lock_anon_vma(page);
842 if (!anon_vma)
843 return ret;
844
845 list_for_each_entry(vma, &anon_vma->head, anon_vma_node) {
Christoph Lameter73523492006-06-23 02:03:27 -0700846 ret = try_to_unmap_one(page, vma, migration);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700847 if (ret == SWAP_FAIL || !page_mapped(page))
848 break;
849 }
Oleg Nesterov34bbd702007-02-28 20:13:49 -0800850
851 page_unlock_anon_vma(anon_vma);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700852 return ret;
853}
854
855/**
856 * try_to_unmap_file - unmap file page using the object-based rmap method
857 * @page: the page to unmap
858 *
859 * Find all the mappings of a page using the mapping pointer and the vma chains
860 * contained in the address_space struct it points to.
861 *
862 * This function is only called from try_to_unmap for object-based pages.
863 */
Christoph Lameter73523492006-06-23 02:03:27 -0700864static int try_to_unmap_file(struct page *page, int migration)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700865{
866 struct address_space *mapping = page->mapping;
867 pgoff_t pgoff = page->index << (PAGE_CACHE_SHIFT - PAGE_SHIFT);
868 struct vm_area_struct *vma;
869 struct prio_tree_iter iter;
870 int ret = SWAP_AGAIN;
871 unsigned long cursor;
872 unsigned long max_nl_cursor = 0;
873 unsigned long max_nl_size = 0;
874 unsigned int mapcount;
875
876 spin_lock(&mapping->i_mmap_lock);
877 vma_prio_tree_foreach(vma, &iter, &mapping->i_mmap, pgoff, pgoff) {
Christoph Lameter73523492006-06-23 02:03:27 -0700878 ret = try_to_unmap_one(page, vma, migration);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700879 if (ret == SWAP_FAIL || !page_mapped(page))
880 goto out;
881 }
882
883 if (list_empty(&mapping->i_mmap_nonlinear))
884 goto out;
885
886 list_for_each_entry(vma, &mapping->i_mmap_nonlinear,
887 shared.vm_set.list) {
Christoph Lametere6a15302006-06-25 05:46:49 -0700888 if ((vma->vm_flags & VM_LOCKED) && !migration)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700889 continue;
890 cursor = (unsigned long) vma->vm_private_data;
891 if (cursor > max_nl_cursor)
892 max_nl_cursor = cursor;
893 cursor = vma->vm_end - vma->vm_start;
894 if (cursor > max_nl_size)
895 max_nl_size = cursor;
896 }
897
898 if (max_nl_size == 0) { /* any nonlinears locked or reserved */
899 ret = SWAP_FAIL;
900 goto out;
901 }
902
903 /*
904 * We don't try to search for this page in the nonlinear vmas,
905 * and page_referenced wouldn't have found it anyway. Instead
906 * just walk the nonlinear vmas trying to age and unmap some.
907 * The mapcount of the page we came in with is irrelevant,
908 * but even so use it as a guide to how hard we should try?
909 */
910 mapcount = page_mapcount(page);
911 if (!mapcount)
912 goto out;
913 cond_resched_lock(&mapping->i_mmap_lock);
914
915 max_nl_size = (max_nl_size + CLUSTER_SIZE - 1) & CLUSTER_MASK;
916 if (max_nl_cursor == 0)
917 max_nl_cursor = CLUSTER_SIZE;
918
919 do {
920 list_for_each_entry(vma, &mapping->i_mmap_nonlinear,
921 shared.vm_set.list) {
Christoph Lametere6a15302006-06-25 05:46:49 -0700922 if ((vma->vm_flags & VM_LOCKED) && !migration)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700923 continue;
924 cursor = (unsigned long) vma->vm_private_data;
Hugh Dickins839b9682005-09-03 15:54:43 -0700925 while ( cursor < max_nl_cursor &&
Linus Torvalds1da177e2005-04-16 15:20:36 -0700926 cursor < vma->vm_end - vma->vm_start) {
927 try_to_unmap_cluster(cursor, &mapcount, vma);
928 cursor += CLUSTER_SIZE;
929 vma->vm_private_data = (void *) cursor;
930 if ((int)mapcount <= 0)
931 goto out;
932 }
933 vma->vm_private_data = (void *) max_nl_cursor;
934 }
935 cond_resched_lock(&mapping->i_mmap_lock);
936 max_nl_cursor += CLUSTER_SIZE;
937 } while (max_nl_cursor <= max_nl_size);
938
939 /*
940 * Don't loop forever (perhaps all the remaining pages are
941 * in locked vmas). Reset cursor on all unreserved nonlinear
942 * vmas, now forgetting on which ones it had fallen behind.
943 */
Hugh Dickins101d2be2005-11-21 21:32:16 -0800944 list_for_each_entry(vma, &mapping->i_mmap_nonlinear, shared.vm_set.list)
945 vma->vm_private_data = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700946out:
947 spin_unlock(&mapping->i_mmap_lock);
948 return ret;
949}
950
951/**
952 * try_to_unmap - try to remove all page table mappings to a page
953 * @page: the page to get unmapped
954 *
955 * Tries to remove all the page table entries which are mapping this
956 * page, used in the pageout path. Caller must hold the page lock.
957 * Return values are:
958 *
959 * SWAP_SUCCESS - we succeeded in removing all mappings
960 * SWAP_AGAIN - we missed a mapping, try again later
961 * SWAP_FAIL - the page is unswappable
962 */
Christoph Lameter73523492006-06-23 02:03:27 -0700963int try_to_unmap(struct page *page, int migration)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700964{
965 int ret;
966
Linus Torvalds1da177e2005-04-16 15:20:36 -0700967 BUG_ON(!PageLocked(page));
968
969 if (PageAnon(page))
Christoph Lameter73523492006-06-23 02:03:27 -0700970 ret = try_to_unmap_anon(page, migration);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700971 else
Christoph Lameter73523492006-06-23 02:03:27 -0700972 ret = try_to_unmap_file(page, migration);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700973
974 if (!page_mapped(page))
975 ret = SWAP_SUCCESS;
976 return ret;
977}
Nikita Danilov81b40822005-05-01 08:58:36 -0700978