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Commit | Line | Data |
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1da177e4 LT |
1 | /* |
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 | * | |
1b1dcc1b | 23 | * inode->i_mutex (while writing or truncating, not reading or faulting) |
82591e6e NP |
24 | * 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) | |
1da177e4 LT |
39 | */ |
40 | ||
41 | #include <linux/mm.h> | |
42 | #include <linux/pagemap.h> | |
43 | #include <linux/swap.h> | |
44 | #include <linux/swapops.h> | |
45 | #include <linux/slab.h> | |
46 | #include <linux/init.h> | |
47 | #include <linux/rmap.h> | |
48 | #include <linux/rcupdate.h> | |
a48d07af | 49 | #include <linux/module.h> |
7de6b805 | 50 | #include <linux/kallsyms.h> |
8a9f3ccd | 51 | #include <linux/memcontrol.h> |
cddb8a5c | 52 | #include <linux/mmu_notifier.h> |
1da177e4 LT |
53 | |
54 | #include <asm/tlbflush.h> | |
55 | ||
fcc234f8 | 56 | struct kmem_cache *anon_vma_cachep; |
1da177e4 | 57 | |
1da177e4 LT |
58 | /* This must be called under the mmap_sem. */ |
59 | int anon_vma_prepare(struct vm_area_struct *vma) | |
60 | { | |
61 | struct anon_vma *anon_vma = vma->anon_vma; | |
62 | ||
63 | might_sleep(); | |
64 | if (unlikely(!anon_vma)) { | |
65 | struct mm_struct *mm = vma->vm_mm; | |
66 | struct anon_vma *allocated, *locked; | |
67 | ||
68 | anon_vma = find_mergeable_anon_vma(vma); | |
69 | if (anon_vma) { | |
70 | allocated = NULL; | |
71 | locked = anon_vma; | |
72 | spin_lock(&locked->lock); | |
73 | } else { | |
74 | anon_vma = anon_vma_alloc(); | |
75 | if (unlikely(!anon_vma)) | |
76 | return -ENOMEM; | |
77 | allocated = anon_vma; | |
78 | locked = NULL; | |
79 | } | |
80 | ||
81 | /* page_table_lock to protect against threads */ | |
82 | spin_lock(&mm->page_table_lock); | |
83 | if (likely(!vma->anon_vma)) { | |
84 | vma->anon_vma = anon_vma; | |
0697212a | 85 | list_add_tail(&vma->anon_vma_node, &anon_vma->head); |
1da177e4 LT |
86 | allocated = NULL; |
87 | } | |
88 | spin_unlock(&mm->page_table_lock); | |
89 | ||
90 | if (locked) | |
91 | spin_unlock(&locked->lock); | |
92 | if (unlikely(allocated)) | |
93 | anon_vma_free(allocated); | |
94 | } | |
95 | return 0; | |
96 | } | |
97 | ||
98 | void __anon_vma_merge(struct vm_area_struct *vma, struct vm_area_struct *next) | |
99 | { | |
100 | BUG_ON(vma->anon_vma != next->anon_vma); | |
101 | list_del(&next->anon_vma_node); | |
102 | } | |
103 | ||
104 | void __anon_vma_link(struct vm_area_struct *vma) | |
105 | { | |
106 | struct anon_vma *anon_vma = vma->anon_vma; | |
107 | ||
30acbaba | 108 | if (anon_vma) |
0697212a | 109 | list_add_tail(&vma->anon_vma_node, &anon_vma->head); |
1da177e4 LT |
110 | } |
111 | ||
112 | void anon_vma_link(struct vm_area_struct *vma) | |
113 | { | |
114 | struct anon_vma *anon_vma = vma->anon_vma; | |
115 | ||
116 | if (anon_vma) { | |
117 | spin_lock(&anon_vma->lock); | |
0697212a | 118 | list_add_tail(&vma->anon_vma_node, &anon_vma->head); |
1da177e4 LT |
119 | spin_unlock(&anon_vma->lock); |
120 | } | |
121 | } | |
122 | ||
123 | void anon_vma_unlink(struct vm_area_struct *vma) | |
124 | { | |
125 | struct anon_vma *anon_vma = vma->anon_vma; | |
126 | int empty; | |
127 | ||
128 | if (!anon_vma) | |
129 | return; | |
130 | ||
131 | spin_lock(&anon_vma->lock); | |
1da177e4 LT |
132 | list_del(&vma->anon_vma_node); |
133 | ||
134 | /* We must garbage collect the anon_vma if it's empty */ | |
135 | empty = list_empty(&anon_vma->head); | |
136 | spin_unlock(&anon_vma->lock); | |
137 | ||
138 | if (empty) | |
139 | anon_vma_free(anon_vma); | |
140 | } | |
141 | ||
51cc5068 | 142 | static void anon_vma_ctor(void *data) |
1da177e4 | 143 | { |
a35afb83 | 144 | struct anon_vma *anon_vma = data; |
1da177e4 | 145 | |
a35afb83 CL |
146 | spin_lock_init(&anon_vma->lock); |
147 | INIT_LIST_HEAD(&anon_vma->head); | |
1da177e4 LT |
148 | } |
149 | ||
150 | void __init anon_vma_init(void) | |
151 | { | |
152 | anon_vma_cachep = kmem_cache_create("anon_vma", sizeof(struct anon_vma), | |
20c2df83 | 153 | 0, SLAB_DESTROY_BY_RCU|SLAB_PANIC, anon_vma_ctor); |
1da177e4 LT |
154 | } |
155 | ||
156 | /* | |
157 | * Getting a lock on a stable anon_vma from a page off the LRU is | |
158 | * tricky: page_lock_anon_vma rely on RCU to guard against the races. | |
159 | */ | |
160 | static struct anon_vma *page_lock_anon_vma(struct page *page) | |
161 | { | |
34bbd704 | 162 | struct anon_vma *anon_vma; |
1da177e4 LT |
163 | unsigned long anon_mapping; |
164 | ||
165 | rcu_read_lock(); | |
166 | anon_mapping = (unsigned long) page->mapping; | |
167 | if (!(anon_mapping & PAGE_MAPPING_ANON)) | |
168 | goto out; | |
169 | if (!page_mapped(page)) | |
170 | goto out; | |
171 | ||
172 | anon_vma = (struct anon_vma *) (anon_mapping - PAGE_MAPPING_ANON); | |
173 | spin_lock(&anon_vma->lock); | |
34bbd704 | 174 | return anon_vma; |
1da177e4 LT |
175 | out: |
176 | rcu_read_unlock(); | |
34bbd704 ON |
177 | return NULL; |
178 | } | |
179 | ||
180 | static void page_unlock_anon_vma(struct anon_vma *anon_vma) | |
181 | { | |
182 | spin_unlock(&anon_vma->lock); | |
183 | rcu_read_unlock(); | |
1da177e4 LT |
184 | } |
185 | ||
186 | /* | |
3ad33b24 LS |
187 | * At what user virtual address is page expected in @vma? |
188 | * Returns virtual address or -EFAULT if page's index/offset is not | |
189 | * within the range mapped the @vma. | |
1da177e4 LT |
190 | */ |
191 | static inline unsigned long | |
192 | vma_address(struct page *page, struct vm_area_struct *vma) | |
193 | { | |
194 | pgoff_t pgoff = page->index << (PAGE_CACHE_SHIFT - PAGE_SHIFT); | |
195 | unsigned long address; | |
196 | ||
197 | address = vma->vm_start + ((pgoff - vma->vm_pgoff) << PAGE_SHIFT); | |
198 | if (unlikely(address < vma->vm_start || address >= vma->vm_end)) { | |
3ad33b24 | 199 | /* page should be within @vma mapping range */ |
1da177e4 LT |
200 | return -EFAULT; |
201 | } | |
202 | return address; | |
203 | } | |
204 | ||
205 | /* | |
206 | * At what user virtual address is page expected in vma? checking that the | |
ee498ed7 | 207 | * page matches the vma: currently only used on anon pages, by unuse_vma; |
1da177e4 LT |
208 | */ |
209 | unsigned long page_address_in_vma(struct page *page, struct vm_area_struct *vma) | |
210 | { | |
211 | if (PageAnon(page)) { | |
212 | if ((void *)vma->anon_vma != | |
213 | (void *)page->mapping - PAGE_MAPPING_ANON) | |
214 | return -EFAULT; | |
215 | } else if (page->mapping && !(vma->vm_flags & VM_NONLINEAR)) { | |
ee498ed7 HD |
216 | if (!vma->vm_file || |
217 | vma->vm_file->f_mapping != page->mapping) | |
1da177e4 LT |
218 | return -EFAULT; |
219 | } else | |
220 | return -EFAULT; | |
221 | return vma_address(page, vma); | |
222 | } | |
223 | ||
81b4082d ND |
224 | /* |
225 | * Check that @page is mapped at @address into @mm. | |
226 | * | |
479db0bf NP |
227 | * If @sync is false, page_check_address may perform a racy check to avoid |
228 | * the page table lock when the pte is not present (helpful when reclaiming | |
229 | * highly shared pages). | |
230 | * | |
b8072f09 | 231 | * On success returns with pte mapped and locked. |
81b4082d | 232 | */ |
ceffc078 | 233 | pte_t *page_check_address(struct page *page, struct mm_struct *mm, |
479db0bf | 234 | unsigned long address, spinlock_t **ptlp, int sync) |
81b4082d ND |
235 | { |
236 | pgd_t *pgd; | |
237 | pud_t *pud; | |
238 | pmd_t *pmd; | |
239 | pte_t *pte; | |
c0718806 | 240 | spinlock_t *ptl; |
81b4082d | 241 | |
81b4082d | 242 | pgd = pgd_offset(mm, address); |
c0718806 HD |
243 | if (!pgd_present(*pgd)) |
244 | return NULL; | |
245 | ||
246 | pud = pud_offset(pgd, address); | |
247 | if (!pud_present(*pud)) | |
248 | return NULL; | |
249 | ||
250 | pmd = pmd_offset(pud, address); | |
251 | if (!pmd_present(*pmd)) | |
252 | return NULL; | |
253 | ||
254 | pte = pte_offset_map(pmd, address); | |
255 | /* Make a quick check before getting the lock */ | |
479db0bf | 256 | if (!sync && !pte_present(*pte)) { |
c0718806 HD |
257 | pte_unmap(pte); |
258 | return NULL; | |
259 | } | |
260 | ||
4c21e2f2 | 261 | ptl = pte_lockptr(mm, pmd); |
c0718806 HD |
262 | spin_lock(ptl); |
263 | if (pte_present(*pte) && page_to_pfn(page) == pte_pfn(*pte)) { | |
264 | *ptlp = ptl; | |
265 | return pte; | |
81b4082d | 266 | } |
c0718806 HD |
267 | pte_unmap_unlock(pte, ptl); |
268 | return NULL; | |
81b4082d ND |
269 | } |
270 | ||
1da177e4 LT |
271 | /* |
272 | * Subfunctions of page_referenced: page_referenced_one called | |
273 | * repeatedly from either page_referenced_anon or page_referenced_file. | |
274 | */ | |
275 | static int page_referenced_one(struct page *page, | |
f7b7fd8f | 276 | struct vm_area_struct *vma, unsigned int *mapcount) |
1da177e4 LT |
277 | { |
278 | struct mm_struct *mm = vma->vm_mm; | |
279 | unsigned long address; | |
1da177e4 | 280 | pte_t *pte; |
c0718806 | 281 | spinlock_t *ptl; |
1da177e4 LT |
282 | int referenced = 0; |
283 | ||
1da177e4 LT |
284 | address = vma_address(page, vma); |
285 | if (address == -EFAULT) | |
286 | goto out; | |
287 | ||
479db0bf | 288 | pte = page_check_address(page, mm, address, &ptl, 0); |
c0718806 HD |
289 | if (!pte) |
290 | goto out; | |
1da177e4 | 291 | |
5a9bbdcd HD |
292 | if (vma->vm_flags & VM_LOCKED) { |
293 | referenced++; | |
294 | *mapcount = 1; /* break early from loop */ | |
cddb8a5c | 295 | } else if (ptep_clear_flush_young_notify(vma, address, pte)) |
c0718806 | 296 | referenced++; |
1da177e4 | 297 | |
c0718806 HD |
298 | /* Pretend the page is referenced if the task has the |
299 | swap token and is in the middle of a page fault. */ | |
f7b7fd8f | 300 | if (mm != current->mm && has_swap_token(mm) && |
c0718806 HD |
301 | rwsem_is_locked(&mm->mmap_sem)) |
302 | referenced++; | |
303 | ||
304 | (*mapcount)--; | |
305 | pte_unmap_unlock(pte, ptl); | |
1da177e4 LT |
306 | out: |
307 | return referenced; | |
308 | } | |
309 | ||
bed7161a BS |
310 | static int page_referenced_anon(struct page *page, |
311 | struct mem_cgroup *mem_cont) | |
1da177e4 LT |
312 | { |
313 | unsigned int mapcount; | |
314 | struct anon_vma *anon_vma; | |
315 | struct vm_area_struct *vma; | |
316 | int referenced = 0; | |
317 | ||
318 | anon_vma = page_lock_anon_vma(page); | |
319 | if (!anon_vma) | |
320 | return referenced; | |
321 | ||
322 | mapcount = page_mapcount(page); | |
323 | list_for_each_entry(vma, &anon_vma->head, anon_vma_node) { | |
bed7161a BS |
324 | /* |
325 | * If we are reclaiming on behalf of a cgroup, skip | |
326 | * counting on behalf of references from different | |
327 | * cgroups | |
328 | */ | |
bd845e38 | 329 | if (mem_cont && !mm_match_cgroup(vma->vm_mm, mem_cont)) |
bed7161a | 330 | continue; |
f7b7fd8f | 331 | referenced += page_referenced_one(page, vma, &mapcount); |
1da177e4 LT |
332 | if (!mapcount) |
333 | break; | |
334 | } | |
34bbd704 ON |
335 | |
336 | page_unlock_anon_vma(anon_vma); | |
1da177e4 LT |
337 | return referenced; |
338 | } | |
339 | ||
340 | /** | |
341 | * page_referenced_file - referenced check for object-based rmap | |
342 | * @page: the page we're checking references on. | |
43d8eac4 | 343 | * @mem_cont: target memory controller |
1da177e4 LT |
344 | * |
345 | * For an object-based mapped page, find all the places it is mapped and | |
346 | * check/clear the referenced flag. This is done by following the page->mapping | |
347 | * pointer, then walking the chain of vmas it holds. It returns the number | |
348 | * of references it found. | |
349 | * | |
350 | * This function is only called from page_referenced for object-based pages. | |
351 | */ | |
bed7161a BS |
352 | static int page_referenced_file(struct page *page, |
353 | struct mem_cgroup *mem_cont) | |
1da177e4 LT |
354 | { |
355 | unsigned int mapcount; | |
356 | struct address_space *mapping = page->mapping; | |
357 | pgoff_t pgoff = page->index << (PAGE_CACHE_SHIFT - PAGE_SHIFT); | |
358 | struct vm_area_struct *vma; | |
359 | struct prio_tree_iter iter; | |
360 | int referenced = 0; | |
361 | ||
362 | /* | |
363 | * The caller's checks on page->mapping and !PageAnon have made | |
364 | * sure that this is a file page: the check for page->mapping | |
365 | * excludes the case just before it gets set on an anon page. | |
366 | */ | |
367 | BUG_ON(PageAnon(page)); | |
368 | ||
369 | /* | |
370 | * The page lock not only makes sure that page->mapping cannot | |
371 | * suddenly be NULLified by truncation, it makes sure that the | |
372 | * structure at mapping cannot be freed and reused yet, | |
373 | * so we can safely take mapping->i_mmap_lock. | |
374 | */ | |
375 | BUG_ON(!PageLocked(page)); | |
376 | ||
377 | spin_lock(&mapping->i_mmap_lock); | |
378 | ||
379 | /* | |
380 | * i_mmap_lock does not stabilize mapcount at all, but mapcount | |
381 | * is more likely to be accurate if we note it after spinning. | |
382 | */ | |
383 | mapcount = page_mapcount(page); | |
384 | ||
385 | vma_prio_tree_foreach(vma, &iter, &mapping->i_mmap, pgoff, pgoff) { | |
bed7161a BS |
386 | /* |
387 | * If we are reclaiming on behalf of a cgroup, skip | |
388 | * counting on behalf of references from different | |
389 | * cgroups | |
390 | */ | |
bd845e38 | 391 | if (mem_cont && !mm_match_cgroup(vma->vm_mm, mem_cont)) |
bed7161a | 392 | continue; |
1da177e4 LT |
393 | if ((vma->vm_flags & (VM_LOCKED|VM_MAYSHARE)) |
394 | == (VM_LOCKED|VM_MAYSHARE)) { | |
395 | referenced++; | |
396 | break; | |
397 | } | |
f7b7fd8f | 398 | referenced += page_referenced_one(page, vma, &mapcount); |
1da177e4 LT |
399 | if (!mapcount) |
400 | break; | |
401 | } | |
402 | ||
403 | spin_unlock(&mapping->i_mmap_lock); | |
404 | return referenced; | |
405 | } | |
406 | ||
407 | /** | |
408 | * page_referenced - test if the page was referenced | |
409 | * @page: the page to test | |
410 | * @is_locked: caller holds lock on the page | |
43d8eac4 | 411 | * @mem_cont: target memory controller |
1da177e4 LT |
412 | * |
413 | * Quick test_and_clear_referenced for all mappings to a page, | |
414 | * returns the number of ptes which referenced the page. | |
415 | */ | |
bed7161a BS |
416 | int page_referenced(struct page *page, int is_locked, |
417 | struct mem_cgroup *mem_cont) | |
1da177e4 LT |
418 | { |
419 | int referenced = 0; | |
420 | ||
1da177e4 LT |
421 | if (TestClearPageReferenced(page)) |
422 | referenced++; | |
423 | ||
424 | if (page_mapped(page) && page->mapping) { | |
425 | if (PageAnon(page)) | |
bed7161a | 426 | referenced += page_referenced_anon(page, mem_cont); |
1da177e4 | 427 | else if (is_locked) |
bed7161a | 428 | referenced += page_referenced_file(page, mem_cont); |
529ae9aa | 429 | else if (!trylock_page(page)) |
1da177e4 LT |
430 | referenced++; |
431 | else { | |
432 | if (page->mapping) | |
bed7161a BS |
433 | referenced += |
434 | page_referenced_file(page, mem_cont); | |
1da177e4 LT |
435 | unlock_page(page); |
436 | } | |
437 | } | |
5b7baf05 CB |
438 | |
439 | if (page_test_and_clear_young(page)) | |
440 | referenced++; | |
441 | ||
1da177e4 LT |
442 | return referenced; |
443 | } | |
444 | ||
d08b3851 PZ |
445 | static int page_mkclean_one(struct page *page, struct vm_area_struct *vma) |
446 | { | |
447 | struct mm_struct *mm = vma->vm_mm; | |
448 | unsigned long address; | |
c2fda5fe | 449 | pte_t *pte; |
d08b3851 PZ |
450 | spinlock_t *ptl; |
451 | int ret = 0; | |
452 | ||
453 | address = vma_address(page, vma); | |
454 | if (address == -EFAULT) | |
455 | goto out; | |
456 | ||
479db0bf | 457 | pte = page_check_address(page, mm, address, &ptl, 1); |
d08b3851 PZ |
458 | if (!pte) |
459 | goto out; | |
460 | ||
c2fda5fe PZ |
461 | if (pte_dirty(*pte) || pte_write(*pte)) { |
462 | pte_t entry; | |
d08b3851 | 463 | |
c2fda5fe | 464 | flush_cache_page(vma, address, pte_pfn(*pte)); |
cddb8a5c | 465 | entry = ptep_clear_flush_notify(vma, address, pte); |
c2fda5fe PZ |
466 | entry = pte_wrprotect(entry); |
467 | entry = pte_mkclean(entry); | |
d6e88e67 | 468 | set_pte_at(mm, address, pte, entry); |
c2fda5fe PZ |
469 | ret = 1; |
470 | } | |
d08b3851 | 471 | |
d08b3851 PZ |
472 | pte_unmap_unlock(pte, ptl); |
473 | out: | |
474 | return ret; | |
475 | } | |
476 | ||
477 | static int page_mkclean_file(struct address_space *mapping, struct page *page) | |
478 | { | |
479 | pgoff_t pgoff = page->index << (PAGE_CACHE_SHIFT - PAGE_SHIFT); | |
480 | struct vm_area_struct *vma; | |
481 | struct prio_tree_iter iter; | |
482 | int ret = 0; | |
483 | ||
484 | BUG_ON(PageAnon(page)); | |
485 | ||
486 | spin_lock(&mapping->i_mmap_lock); | |
487 | vma_prio_tree_foreach(vma, &iter, &mapping->i_mmap, pgoff, pgoff) { | |
488 | if (vma->vm_flags & VM_SHARED) | |
489 | ret += page_mkclean_one(page, vma); | |
490 | } | |
491 | spin_unlock(&mapping->i_mmap_lock); | |
492 | return ret; | |
493 | } | |
494 | ||
495 | int page_mkclean(struct page *page) | |
496 | { | |
497 | int ret = 0; | |
498 | ||
499 | BUG_ON(!PageLocked(page)); | |
500 | ||
501 | if (page_mapped(page)) { | |
502 | struct address_space *mapping = page_mapping(page); | |
ce7e9fae | 503 | if (mapping) { |
d08b3851 | 504 | ret = page_mkclean_file(mapping, page); |
ce7e9fae CB |
505 | if (page_test_dirty(page)) { |
506 | page_clear_dirty(page); | |
507 | ret = 1; | |
508 | } | |
6c210482 | 509 | } |
d08b3851 PZ |
510 | } |
511 | ||
512 | return ret; | |
513 | } | |
60b59bea | 514 | EXPORT_SYMBOL_GPL(page_mkclean); |
d08b3851 | 515 | |
9617d95e | 516 | /** |
43d8eac4 | 517 | * __page_set_anon_rmap - setup new anonymous rmap |
9617d95e NP |
518 | * @page: the page to add the mapping to |
519 | * @vma: the vm area in which the mapping is added | |
520 | * @address: the user virtual address mapped | |
521 | */ | |
522 | static void __page_set_anon_rmap(struct page *page, | |
523 | struct vm_area_struct *vma, unsigned long address) | |
524 | { | |
525 | struct anon_vma *anon_vma = vma->anon_vma; | |
526 | ||
527 | BUG_ON(!anon_vma); | |
528 | anon_vma = (void *) anon_vma + PAGE_MAPPING_ANON; | |
529 | page->mapping = (struct address_space *) anon_vma; | |
530 | ||
531 | page->index = linear_page_index(vma, address); | |
532 | ||
a74609fa NP |
533 | /* |
534 | * nr_mapped state can be updated without turning off | |
535 | * interrupts because it is not modified via interrupt. | |
536 | */ | |
f3dbd344 | 537 | __inc_zone_page_state(page, NR_ANON_PAGES); |
9617d95e NP |
538 | } |
539 | ||
c97a9e10 | 540 | /** |
43d8eac4 | 541 | * __page_check_anon_rmap - sanity check anonymous rmap addition |
c97a9e10 NP |
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 | */ | |
546 | static void __page_check_anon_rmap(struct page *page, | |
547 | struct vm_area_struct *vma, unsigned long address) | |
548 | { | |
549 | #ifdef CONFIG_DEBUG_VM | |
550 | /* | |
551 | * The page's anon-rmap details (mapping and index) are guaranteed to | |
552 | * be set up correctly at this point. | |
553 | * | |
554 | * We have exclusion against page_add_anon_rmap because the caller | |
555 | * always holds the page locked, except if called from page_dup_rmap, | |
556 | * in which case the page is already known to be setup. | |
557 | * | |
558 | * We have exclusion against page_add_new_anon_rmap because those pages | |
559 | * are initially only visible via the pagetables, and the pte is locked | |
560 | * over the call to page_add_new_anon_rmap. | |
561 | */ | |
562 | struct anon_vma *anon_vma = vma->anon_vma; | |
563 | anon_vma = (void *) anon_vma + PAGE_MAPPING_ANON; | |
564 | BUG_ON(page->mapping != (struct address_space *)anon_vma); | |
565 | BUG_ON(page->index != linear_page_index(vma, address)); | |
566 | #endif | |
567 | } | |
568 | ||
1da177e4 LT |
569 | /** |
570 | * page_add_anon_rmap - add pte mapping to an anonymous page | |
571 | * @page: the page to add the mapping to | |
572 | * @vma: the vm area in which the mapping is added | |
573 | * @address: the user virtual address mapped | |
574 | * | |
c97a9e10 | 575 | * The caller needs to hold the pte lock and the page must be locked. |
1da177e4 LT |
576 | */ |
577 | void page_add_anon_rmap(struct page *page, | |
578 | struct vm_area_struct *vma, unsigned long address) | |
579 | { | |
c97a9e10 NP |
580 | VM_BUG_ON(!PageLocked(page)); |
581 | VM_BUG_ON(address < vma->vm_start || address >= vma->vm_end); | |
9617d95e NP |
582 | if (atomic_inc_and_test(&page->_mapcount)) |
583 | __page_set_anon_rmap(page, vma, address); | |
69029cd5 | 584 | else |
c97a9e10 | 585 | __page_check_anon_rmap(page, vma, address); |
1da177e4 LT |
586 | } |
587 | ||
43d8eac4 | 588 | /** |
9617d95e NP |
589 | * page_add_new_anon_rmap - add pte mapping to a new anonymous page |
590 | * @page: the page to add the mapping to | |
591 | * @vma: the vm area in which the mapping is added | |
592 | * @address: the user virtual address mapped | |
593 | * | |
594 | * Same as page_add_anon_rmap but must only be called on *new* pages. | |
595 | * This means the inc-and-test can be bypassed. | |
c97a9e10 | 596 | * Page does not have to be locked. |
9617d95e NP |
597 | */ |
598 | void page_add_new_anon_rmap(struct page *page, | |
599 | struct vm_area_struct *vma, unsigned long address) | |
600 | { | |
c97a9e10 | 601 | BUG_ON(address < vma->vm_start || address >= vma->vm_end); |
9617d95e NP |
602 | atomic_set(&page->_mapcount, 0); /* elevate count by 1 (starts at -1) */ |
603 | __page_set_anon_rmap(page, vma, address); | |
604 | } | |
605 | ||
1da177e4 LT |
606 | /** |
607 | * page_add_file_rmap - add pte mapping to a file page | |
608 | * @page: the page to add the mapping to | |
609 | * | |
b8072f09 | 610 | * The caller needs to hold the pte lock. |
1da177e4 LT |
611 | */ |
612 | void page_add_file_rmap(struct page *page) | |
613 | { | |
1da177e4 | 614 | if (atomic_inc_and_test(&page->_mapcount)) |
65ba55f5 | 615 | __inc_zone_page_state(page, NR_FILE_MAPPED); |
1da177e4 LT |
616 | } |
617 | ||
c97a9e10 NP |
618 | #ifdef CONFIG_DEBUG_VM |
619 | /** | |
620 | * page_dup_rmap - duplicate pte mapping to a page | |
621 | * @page: the page to add the mapping to | |
43d8eac4 RD |
622 | * @vma: the vm area being duplicated |
623 | * @address: the user virtual address mapped | |
c97a9e10 NP |
624 | * |
625 | * For copy_page_range only: minimal extract from page_add_file_rmap / | |
626 | * page_add_anon_rmap, avoiding unnecessary tests (already checked) so it's | |
627 | * quicker. | |
628 | * | |
629 | * The caller needs to hold the pte lock. | |
630 | */ | |
631 | void page_dup_rmap(struct page *page, struct vm_area_struct *vma, unsigned long address) | |
632 | { | |
633 | BUG_ON(page_mapcount(page) == 0); | |
634 | if (PageAnon(page)) | |
635 | __page_check_anon_rmap(page, vma, address); | |
636 | atomic_inc(&page->_mapcount); | |
637 | } | |
638 | #endif | |
639 | ||
1da177e4 LT |
640 | /** |
641 | * page_remove_rmap - take down pte mapping from a page | |
642 | * @page: page to remove mapping from | |
43d8eac4 | 643 | * @vma: the vm area in which the mapping is removed |
1da177e4 | 644 | * |
b8072f09 | 645 | * The caller needs to hold the pte lock. |
1da177e4 | 646 | */ |
7de6b805 | 647 | void page_remove_rmap(struct page *page, struct vm_area_struct *vma) |
1da177e4 | 648 | { |
1da177e4 | 649 | if (atomic_add_negative(-1, &page->_mapcount)) { |
b7ab795b | 650 | if (unlikely(page_mapcount(page) < 0)) { |
ef2bf0dc | 651 | printk (KERN_EMERG "Eeek! page_mapcount(page) went negative! (%d)\n", page_mapcount(page)); |
7de6b805 | 652 | printk (KERN_EMERG " page pfn = %lx\n", page_to_pfn(page)); |
ef2bf0dc DJ |
653 | printk (KERN_EMERG " page->flags = %lx\n", page->flags); |
654 | printk (KERN_EMERG " page->count = %x\n", page_count(page)); | |
655 | printk (KERN_EMERG " page->mapping = %p\n", page->mapping); | |
7de6b805 | 656 | print_symbol (KERN_EMERG " vma->vm_ops = %s\n", (unsigned long)vma->vm_ops); |
54cb8821 | 657 | if (vma->vm_ops) { |
54cb8821 NP |
658 | print_symbol (KERN_EMERG " vma->vm_ops->fault = %s\n", (unsigned long)vma->vm_ops->fault); |
659 | } | |
7de6b805 NP |
660 | if (vma->vm_file && vma->vm_file->f_op) |
661 | print_symbol (KERN_EMERG " vma->vm_file->f_op->mmap = %s\n", (unsigned long)vma->vm_file->f_op->mmap); | |
b16bc64d | 662 | BUG(); |
ef2bf0dc | 663 | } |
b16bc64d | 664 | |
1da177e4 | 665 | /* |
16f8c5b2 HD |
666 | * Now that the last pte has gone, s390 must transfer dirty |
667 | * flag from storage key to struct page. We can usually skip | |
668 | * this if the page is anon, so about to be freed; but perhaps | |
669 | * not if it's in swapcache - there might be another pte slot | |
670 | * containing the swap entry, but page not yet written to swap. | |
1da177e4 | 671 | */ |
a4b526b3 MS |
672 | if ((!PageAnon(page) || PageSwapCache(page)) && |
673 | page_test_dirty(page)) { | |
6c210482 | 674 | page_clear_dirty(page); |
1da177e4 | 675 | set_page_dirty(page); |
6c210482 | 676 | } |
8a9f3ccd | 677 | |
16f8c5b2 | 678 | mem_cgroup_uncharge_page(page); |
f3dbd344 | 679 | __dec_zone_page_state(page, |
16f8c5b2 HD |
680 | PageAnon(page) ? NR_ANON_PAGES : NR_FILE_MAPPED); |
681 | /* | |
682 | * It would be tidy to reset the PageAnon mapping here, | |
683 | * but that might overwrite a racing page_add_anon_rmap | |
684 | * which increments mapcount after us but sets mapping | |
685 | * before us: so leave the reset to free_hot_cold_page, | |
686 | * and remember that it's only reliable while mapped. | |
687 | * Leaving it set also helps swapoff to reinstate ptes | |
688 | * faster for those pages still in swapcache. | |
689 | */ | |
1da177e4 LT |
690 | } |
691 | } | |
692 | ||
693 | /* | |
694 | * Subfunctions of try_to_unmap: try_to_unmap_one called | |
695 | * repeatedly from either try_to_unmap_anon or try_to_unmap_file. | |
696 | */ | |
a48d07af | 697 | static int try_to_unmap_one(struct page *page, struct vm_area_struct *vma, |
7352349a | 698 | int migration) |
1da177e4 LT |
699 | { |
700 | struct mm_struct *mm = vma->vm_mm; | |
701 | unsigned long address; | |
1da177e4 LT |
702 | pte_t *pte; |
703 | pte_t pteval; | |
c0718806 | 704 | spinlock_t *ptl; |
1da177e4 LT |
705 | int ret = SWAP_AGAIN; |
706 | ||
1da177e4 LT |
707 | address = vma_address(page, vma); |
708 | if (address == -EFAULT) | |
709 | goto out; | |
710 | ||
479db0bf | 711 | pte = page_check_address(page, mm, address, &ptl, 0); |
c0718806 | 712 | if (!pte) |
81b4082d | 713 | goto out; |
1da177e4 LT |
714 | |
715 | /* | |
716 | * If the page is mlock()d, we cannot swap it out. | |
717 | * If it's recently referenced (perhaps page_referenced | |
718 | * skipped over this mm) then we should reactivate it. | |
719 | */ | |
e6a1530d | 720 | if (!migration && ((vma->vm_flags & VM_LOCKED) || |
cddb8a5c | 721 | (ptep_clear_flush_young_notify(vma, address, pte)))) { |
1da177e4 LT |
722 | ret = SWAP_FAIL; |
723 | goto out_unmap; | |
724 | } | |
725 | ||
1da177e4 LT |
726 | /* Nuke the page table entry. */ |
727 | flush_cache_page(vma, address, page_to_pfn(page)); | |
cddb8a5c | 728 | pteval = ptep_clear_flush_notify(vma, address, pte); |
1da177e4 LT |
729 | |
730 | /* Move the dirty bit to the physical page now the pte is gone. */ | |
731 | if (pte_dirty(pteval)) | |
732 | set_page_dirty(page); | |
733 | ||
365e9c87 HD |
734 | /* Update high watermark before we lower rss */ |
735 | update_hiwater_rss(mm); | |
736 | ||
1da177e4 | 737 | if (PageAnon(page)) { |
4c21e2f2 | 738 | swp_entry_t entry = { .val = page_private(page) }; |
0697212a CL |
739 | |
740 | if (PageSwapCache(page)) { | |
741 | /* | |
742 | * Store the swap location in the pte. | |
743 | * See handle_pte_fault() ... | |
744 | */ | |
745 | swap_duplicate(entry); | |
746 | if (list_empty(&mm->mmlist)) { | |
747 | spin_lock(&mmlist_lock); | |
748 | if (list_empty(&mm->mmlist)) | |
749 | list_add(&mm->mmlist, &init_mm.mmlist); | |
750 | spin_unlock(&mmlist_lock); | |
751 | } | |
442c9137 | 752 | dec_mm_counter(mm, anon_rss); |
04e62a29 | 753 | #ifdef CONFIG_MIGRATION |
0697212a CL |
754 | } else { |
755 | /* | |
756 | * Store the pfn of the page in a special migration | |
757 | * pte. do_swap_page() will wait until the migration | |
758 | * pte is removed and then restart fault handling. | |
759 | */ | |
760 | BUG_ON(!migration); | |
761 | entry = make_migration_entry(page, pte_write(pteval)); | |
04e62a29 | 762 | #endif |
1da177e4 LT |
763 | } |
764 | set_pte_at(mm, address, pte, swp_entry_to_pte(entry)); | |
765 | BUG_ON(pte_file(*pte)); | |
4294621f | 766 | } else |
04e62a29 CL |
767 | #ifdef CONFIG_MIGRATION |
768 | if (migration) { | |
769 | /* Establish migration entry for a file page */ | |
770 | swp_entry_t entry; | |
771 | entry = make_migration_entry(page, pte_write(pteval)); | |
772 | set_pte_at(mm, address, pte, swp_entry_to_pte(entry)); | |
773 | } else | |
774 | #endif | |
4294621f | 775 | dec_mm_counter(mm, file_rss); |
1da177e4 | 776 | |
04e62a29 | 777 | |
7de6b805 | 778 | page_remove_rmap(page, vma); |
1da177e4 LT |
779 | page_cache_release(page); |
780 | ||
781 | out_unmap: | |
c0718806 | 782 | pte_unmap_unlock(pte, ptl); |
1da177e4 LT |
783 | out: |
784 | return ret; | |
785 | } | |
786 | ||
787 | /* | |
788 | * objrmap doesn't work for nonlinear VMAs because the assumption that | |
789 | * offset-into-file correlates with offset-into-virtual-addresses does not hold. | |
790 | * Consequently, given a particular page and its ->index, we cannot locate the | |
791 | * ptes which are mapping that page without an exhaustive linear search. | |
792 | * | |
793 | * So what this code does is a mini "virtual scan" of each nonlinear VMA which | |
794 | * maps the file to which the target page belongs. The ->vm_private_data field | |
795 | * holds the current cursor into that scan. Successive searches will circulate | |
796 | * around the vma's virtual address space. | |
797 | * | |
798 | * So as more replacement pressure is applied to the pages in a nonlinear VMA, | |
799 | * more scanning pressure is placed against them as well. Eventually pages | |
800 | * will become fully unmapped and are eligible for eviction. | |
801 | * | |
802 | * For very sparsely populated VMAs this is a little inefficient - chances are | |
803 | * there there won't be many ptes located within the scan cluster. In this case | |
804 | * maybe we could scan further - to the end of the pte page, perhaps. | |
805 | */ | |
806 | #define CLUSTER_SIZE min(32*PAGE_SIZE, PMD_SIZE) | |
807 | #define CLUSTER_MASK (~(CLUSTER_SIZE - 1)) | |
808 | ||
809 | static void try_to_unmap_cluster(unsigned long cursor, | |
810 | unsigned int *mapcount, struct vm_area_struct *vma) | |
811 | { | |
812 | struct mm_struct *mm = vma->vm_mm; | |
813 | pgd_t *pgd; | |
814 | pud_t *pud; | |
815 | pmd_t *pmd; | |
c0718806 | 816 | pte_t *pte; |
1da177e4 | 817 | pte_t pteval; |
c0718806 | 818 | spinlock_t *ptl; |
1da177e4 LT |
819 | struct page *page; |
820 | unsigned long address; | |
821 | unsigned long end; | |
1da177e4 | 822 | |
1da177e4 LT |
823 | address = (vma->vm_start + cursor) & CLUSTER_MASK; |
824 | end = address + CLUSTER_SIZE; | |
825 | if (address < vma->vm_start) | |
826 | address = vma->vm_start; | |
827 | if (end > vma->vm_end) | |
828 | end = vma->vm_end; | |
829 | ||
830 | pgd = pgd_offset(mm, address); | |
831 | if (!pgd_present(*pgd)) | |
c0718806 | 832 | return; |
1da177e4 LT |
833 | |
834 | pud = pud_offset(pgd, address); | |
835 | if (!pud_present(*pud)) | |
c0718806 | 836 | return; |
1da177e4 LT |
837 | |
838 | pmd = pmd_offset(pud, address); | |
839 | if (!pmd_present(*pmd)) | |
c0718806 HD |
840 | return; |
841 | ||
842 | pte = pte_offset_map_lock(mm, pmd, address, &ptl); | |
1da177e4 | 843 | |
365e9c87 HD |
844 | /* Update high watermark before we lower rss */ |
845 | update_hiwater_rss(mm); | |
846 | ||
c0718806 | 847 | for (; address < end; pte++, address += PAGE_SIZE) { |
1da177e4 LT |
848 | if (!pte_present(*pte)) |
849 | continue; | |
6aab341e LT |
850 | page = vm_normal_page(vma, address, *pte); |
851 | BUG_ON(!page || PageAnon(page)); | |
1da177e4 | 852 | |
cddb8a5c | 853 | if (ptep_clear_flush_young_notify(vma, address, pte)) |
1da177e4 LT |
854 | continue; |
855 | ||
856 | /* Nuke the page table entry. */ | |
eca35133 | 857 | flush_cache_page(vma, address, pte_pfn(*pte)); |
cddb8a5c | 858 | pteval = ptep_clear_flush_notify(vma, address, pte); |
1da177e4 LT |
859 | |
860 | /* If nonlinear, store the file page offset in the pte. */ | |
861 | if (page->index != linear_page_index(vma, address)) | |
862 | set_pte_at(mm, address, pte, pgoff_to_pte(page->index)); | |
863 | ||
864 | /* Move the dirty bit to the physical page now the pte is gone. */ | |
865 | if (pte_dirty(pteval)) | |
866 | set_page_dirty(page); | |
867 | ||
7de6b805 | 868 | page_remove_rmap(page, vma); |
1da177e4 | 869 | page_cache_release(page); |
4294621f | 870 | dec_mm_counter(mm, file_rss); |
1da177e4 LT |
871 | (*mapcount)--; |
872 | } | |
c0718806 | 873 | pte_unmap_unlock(pte - 1, ptl); |
1da177e4 LT |
874 | } |
875 | ||
7352349a | 876 | static int try_to_unmap_anon(struct page *page, int migration) |
1da177e4 LT |
877 | { |
878 | struct anon_vma *anon_vma; | |
879 | struct vm_area_struct *vma; | |
880 | int ret = SWAP_AGAIN; | |
881 | ||
882 | anon_vma = page_lock_anon_vma(page); | |
883 | if (!anon_vma) | |
884 | return ret; | |
885 | ||
886 | list_for_each_entry(vma, &anon_vma->head, anon_vma_node) { | |
7352349a | 887 | ret = try_to_unmap_one(page, vma, migration); |
1da177e4 LT |
888 | if (ret == SWAP_FAIL || !page_mapped(page)) |
889 | break; | |
890 | } | |
34bbd704 ON |
891 | |
892 | page_unlock_anon_vma(anon_vma); | |
1da177e4 LT |
893 | return ret; |
894 | } | |
895 | ||
896 | /** | |
897 | * try_to_unmap_file - unmap file page using the object-based rmap method | |
898 | * @page: the page to unmap | |
43d8eac4 | 899 | * @migration: migration flag |
1da177e4 LT |
900 | * |
901 | * Find all the mappings of a page using the mapping pointer and the vma chains | |
902 | * contained in the address_space struct it points to. | |
903 | * | |
904 | * This function is only called from try_to_unmap for object-based pages. | |
905 | */ | |
7352349a | 906 | static int try_to_unmap_file(struct page *page, int migration) |
1da177e4 LT |
907 | { |
908 | struct address_space *mapping = page->mapping; | |
909 | pgoff_t pgoff = page->index << (PAGE_CACHE_SHIFT - PAGE_SHIFT); | |
910 | struct vm_area_struct *vma; | |
911 | struct prio_tree_iter iter; | |
912 | int ret = SWAP_AGAIN; | |
913 | unsigned long cursor; | |
914 | unsigned long max_nl_cursor = 0; | |
915 | unsigned long max_nl_size = 0; | |
916 | unsigned int mapcount; | |
917 | ||
918 | spin_lock(&mapping->i_mmap_lock); | |
919 | vma_prio_tree_foreach(vma, &iter, &mapping->i_mmap, pgoff, pgoff) { | |
7352349a | 920 | ret = try_to_unmap_one(page, vma, migration); |
1da177e4 LT |
921 | if (ret == SWAP_FAIL || !page_mapped(page)) |
922 | goto out; | |
923 | } | |
924 | ||
925 | if (list_empty(&mapping->i_mmap_nonlinear)) | |
926 | goto out; | |
927 | ||
928 | list_for_each_entry(vma, &mapping->i_mmap_nonlinear, | |
929 | shared.vm_set.list) { | |
e6a1530d | 930 | if ((vma->vm_flags & VM_LOCKED) && !migration) |
1da177e4 LT |
931 | continue; |
932 | cursor = (unsigned long) vma->vm_private_data; | |
933 | if (cursor > max_nl_cursor) | |
934 | max_nl_cursor = cursor; | |
935 | cursor = vma->vm_end - vma->vm_start; | |
936 | if (cursor > max_nl_size) | |
937 | max_nl_size = cursor; | |
938 | } | |
939 | ||
940 | if (max_nl_size == 0) { /* any nonlinears locked or reserved */ | |
941 | ret = SWAP_FAIL; | |
942 | goto out; | |
943 | } | |
944 | ||
945 | /* | |
946 | * We don't try to search for this page in the nonlinear vmas, | |
947 | * and page_referenced wouldn't have found it anyway. Instead | |
948 | * just walk the nonlinear vmas trying to age and unmap some. | |
949 | * The mapcount of the page we came in with is irrelevant, | |
950 | * but even so use it as a guide to how hard we should try? | |
951 | */ | |
952 | mapcount = page_mapcount(page); | |
953 | if (!mapcount) | |
954 | goto out; | |
955 | cond_resched_lock(&mapping->i_mmap_lock); | |
956 | ||
957 | max_nl_size = (max_nl_size + CLUSTER_SIZE - 1) & CLUSTER_MASK; | |
958 | if (max_nl_cursor == 0) | |
959 | max_nl_cursor = CLUSTER_SIZE; | |
960 | ||
961 | do { | |
962 | list_for_each_entry(vma, &mapping->i_mmap_nonlinear, | |
963 | shared.vm_set.list) { | |
e6a1530d | 964 | if ((vma->vm_flags & VM_LOCKED) && !migration) |
1da177e4 LT |
965 | continue; |
966 | cursor = (unsigned long) vma->vm_private_data; | |
839b9685 | 967 | while ( cursor < max_nl_cursor && |
1da177e4 LT |
968 | cursor < vma->vm_end - vma->vm_start) { |
969 | try_to_unmap_cluster(cursor, &mapcount, vma); | |
970 | cursor += CLUSTER_SIZE; | |
971 | vma->vm_private_data = (void *) cursor; | |
972 | if ((int)mapcount <= 0) | |
973 | goto out; | |
974 | } | |
975 | vma->vm_private_data = (void *) max_nl_cursor; | |
976 | } | |
977 | cond_resched_lock(&mapping->i_mmap_lock); | |
978 | max_nl_cursor += CLUSTER_SIZE; | |
979 | } while (max_nl_cursor <= max_nl_size); | |
980 | ||
981 | /* | |
982 | * Don't loop forever (perhaps all the remaining pages are | |
983 | * in locked vmas). Reset cursor on all unreserved nonlinear | |
984 | * vmas, now forgetting on which ones it had fallen behind. | |
985 | */ | |
101d2be7 HD |
986 | list_for_each_entry(vma, &mapping->i_mmap_nonlinear, shared.vm_set.list) |
987 | vma->vm_private_data = NULL; | |
1da177e4 LT |
988 | out: |
989 | spin_unlock(&mapping->i_mmap_lock); | |
990 | return ret; | |
991 | } | |
992 | ||
993 | /** | |
994 | * try_to_unmap - try to remove all page table mappings to a page | |
995 | * @page: the page to get unmapped | |
43d8eac4 | 996 | * @migration: migration flag |
1da177e4 LT |
997 | * |
998 | * Tries to remove all the page table entries which are mapping this | |
999 | * page, used in the pageout path. Caller must hold the page lock. | |
1000 | * Return values are: | |
1001 | * | |
1002 | * SWAP_SUCCESS - we succeeded in removing all mappings | |
1003 | * SWAP_AGAIN - we missed a mapping, try again later | |
1004 | * SWAP_FAIL - the page is unswappable | |
1005 | */ | |
7352349a | 1006 | int try_to_unmap(struct page *page, int migration) |
1da177e4 LT |
1007 | { |
1008 | int ret; | |
1009 | ||
1da177e4 LT |
1010 | BUG_ON(!PageLocked(page)); |
1011 | ||
1012 | if (PageAnon(page)) | |
7352349a | 1013 | ret = try_to_unmap_anon(page, migration); |
1da177e4 | 1014 | else |
7352349a | 1015 | ret = try_to_unmap_file(page, migration); |
1da177e4 LT |
1016 | |
1017 | if (!page_mapped(page)) | |
1018 | ret = SWAP_SUCCESS; | |
1019 | return ret; | |
1020 | } | |
81b4082d | 1021 |