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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 | |
98f32602 | 17 | * Contributions by Hugh Dickins 2003, 2004 |
1da177e4 LT |
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) | |
6a46079c AK |
39 | * |
40 | * (code doesn't rely on that order so it could be switched around) | |
41 | * ->tasklist_lock | |
42 | * anon_vma->lock (memory_failure, collect_procs_anon) | |
43 | * pte map lock | |
1da177e4 LT |
44 | */ |
45 | ||
46 | #include <linux/mm.h> | |
47 | #include <linux/pagemap.h> | |
48 | #include <linux/swap.h> | |
49 | #include <linux/swapops.h> | |
50 | #include <linux/slab.h> | |
51 | #include <linux/init.h> | |
5ad64688 | 52 | #include <linux/ksm.h> |
1da177e4 LT |
53 | #include <linux/rmap.h> |
54 | #include <linux/rcupdate.h> | |
a48d07af | 55 | #include <linux/module.h> |
8a9f3ccd | 56 | #include <linux/memcontrol.h> |
cddb8a5c | 57 | #include <linux/mmu_notifier.h> |
64cdd548 | 58 | #include <linux/migrate.h> |
0fe6e20b | 59 | #include <linux/hugetlb.h> |
1da177e4 LT |
60 | |
61 | #include <asm/tlbflush.h> | |
62 | ||
b291f000 NP |
63 | #include "internal.h" |
64 | ||
fdd2e5f8 | 65 | static struct kmem_cache *anon_vma_cachep; |
5beb4930 | 66 | static struct kmem_cache *anon_vma_chain_cachep; |
fdd2e5f8 AB |
67 | |
68 | static inline struct anon_vma *anon_vma_alloc(void) | |
69 | { | |
70 | return kmem_cache_alloc(anon_vma_cachep, GFP_KERNEL); | |
71 | } | |
72 | ||
db114b83 | 73 | void anon_vma_free(struct anon_vma *anon_vma) |
fdd2e5f8 AB |
74 | { |
75 | kmem_cache_free(anon_vma_cachep, anon_vma); | |
76 | } | |
1da177e4 | 77 | |
5beb4930 RR |
78 | static inline struct anon_vma_chain *anon_vma_chain_alloc(void) |
79 | { | |
80 | return kmem_cache_alloc(anon_vma_chain_cachep, GFP_KERNEL); | |
81 | } | |
82 | ||
83 | void anon_vma_chain_free(struct anon_vma_chain *anon_vma_chain) | |
84 | { | |
85 | kmem_cache_free(anon_vma_chain_cachep, anon_vma_chain); | |
86 | } | |
87 | ||
d9d332e0 LT |
88 | /** |
89 | * anon_vma_prepare - attach an anon_vma to a memory region | |
90 | * @vma: the memory region in question | |
91 | * | |
92 | * This makes sure the memory mapping described by 'vma' has | |
93 | * an 'anon_vma' attached to it, so that we can associate the | |
94 | * anonymous pages mapped into it with that anon_vma. | |
95 | * | |
96 | * The common case will be that we already have one, but if | |
97 | * if not we either need to find an adjacent mapping that we | |
98 | * can re-use the anon_vma from (very common when the only | |
99 | * reason for splitting a vma has been mprotect()), or we | |
100 | * allocate a new one. | |
101 | * | |
102 | * Anon-vma allocations are very subtle, because we may have | |
103 | * optimistically looked up an anon_vma in page_lock_anon_vma() | |
104 | * and that may actually touch the spinlock even in the newly | |
105 | * allocated vma (it depends on RCU to make sure that the | |
106 | * anon_vma isn't actually destroyed). | |
107 | * | |
108 | * As a result, we need to do proper anon_vma locking even | |
109 | * for the new allocation. At the same time, we do not want | |
110 | * to do any locking for the common case of already having | |
111 | * an anon_vma. | |
112 | * | |
113 | * This must be called with the mmap_sem held for reading. | |
114 | */ | |
1da177e4 LT |
115 | int anon_vma_prepare(struct vm_area_struct *vma) |
116 | { | |
117 | struct anon_vma *anon_vma = vma->anon_vma; | |
5beb4930 | 118 | struct anon_vma_chain *avc; |
1da177e4 LT |
119 | |
120 | might_sleep(); | |
121 | if (unlikely(!anon_vma)) { | |
122 | struct mm_struct *mm = vma->vm_mm; | |
d9d332e0 | 123 | struct anon_vma *allocated; |
1da177e4 | 124 | |
5beb4930 RR |
125 | avc = anon_vma_chain_alloc(); |
126 | if (!avc) | |
127 | goto out_enomem; | |
128 | ||
1da177e4 | 129 | anon_vma = find_mergeable_anon_vma(vma); |
d9d332e0 LT |
130 | allocated = NULL; |
131 | if (!anon_vma) { | |
1da177e4 LT |
132 | anon_vma = anon_vma_alloc(); |
133 | if (unlikely(!anon_vma)) | |
5beb4930 | 134 | goto out_enomem_free_avc; |
1da177e4 | 135 | allocated = anon_vma; |
1da177e4 LT |
136 | } |
137 | ||
31f2b0eb | 138 | spin_lock(&anon_vma->lock); |
1da177e4 LT |
139 | /* page_table_lock to protect against threads */ |
140 | spin_lock(&mm->page_table_lock); | |
141 | if (likely(!vma->anon_vma)) { | |
142 | vma->anon_vma = anon_vma; | |
5beb4930 RR |
143 | avc->anon_vma = anon_vma; |
144 | avc->vma = vma; | |
145 | list_add(&avc->same_vma, &vma->anon_vma_chain); | |
146 | list_add(&avc->same_anon_vma, &anon_vma->head); | |
1da177e4 | 147 | allocated = NULL; |
31f2b0eb | 148 | avc = NULL; |
1da177e4 LT |
149 | } |
150 | spin_unlock(&mm->page_table_lock); | |
d9d332e0 | 151 | spin_unlock(&anon_vma->lock); |
31f2b0eb ON |
152 | |
153 | if (unlikely(allocated)) | |
1da177e4 | 154 | anon_vma_free(allocated); |
31f2b0eb | 155 | if (unlikely(avc)) |
5beb4930 | 156 | anon_vma_chain_free(avc); |
1da177e4 LT |
157 | } |
158 | return 0; | |
5beb4930 RR |
159 | |
160 | out_enomem_free_avc: | |
161 | anon_vma_chain_free(avc); | |
162 | out_enomem: | |
163 | return -ENOMEM; | |
1da177e4 LT |
164 | } |
165 | ||
5beb4930 RR |
166 | static void anon_vma_chain_link(struct vm_area_struct *vma, |
167 | struct anon_vma_chain *avc, | |
168 | struct anon_vma *anon_vma) | |
1da177e4 | 169 | { |
5beb4930 RR |
170 | avc->vma = vma; |
171 | avc->anon_vma = anon_vma; | |
172 | list_add(&avc->same_vma, &vma->anon_vma_chain); | |
173 | ||
174 | spin_lock(&anon_vma->lock); | |
175 | list_add_tail(&avc->same_anon_vma, &anon_vma->head); | |
176 | spin_unlock(&anon_vma->lock); | |
1da177e4 LT |
177 | } |
178 | ||
5beb4930 RR |
179 | /* |
180 | * Attach the anon_vmas from src to dst. | |
181 | * Returns 0 on success, -ENOMEM on failure. | |
182 | */ | |
183 | int anon_vma_clone(struct vm_area_struct *dst, struct vm_area_struct *src) | |
1da177e4 | 184 | { |
5beb4930 RR |
185 | struct anon_vma_chain *avc, *pavc; |
186 | ||
646d87b4 | 187 | list_for_each_entry_reverse(pavc, &src->anon_vma_chain, same_vma) { |
5beb4930 RR |
188 | avc = anon_vma_chain_alloc(); |
189 | if (!avc) | |
190 | goto enomem_failure; | |
191 | anon_vma_chain_link(dst, avc, pavc->anon_vma); | |
192 | } | |
193 | return 0; | |
1da177e4 | 194 | |
5beb4930 RR |
195 | enomem_failure: |
196 | unlink_anon_vmas(dst); | |
197 | return -ENOMEM; | |
1da177e4 LT |
198 | } |
199 | ||
5beb4930 RR |
200 | /* |
201 | * Attach vma to its own anon_vma, as well as to the anon_vmas that | |
202 | * the corresponding VMA in the parent process is attached to. | |
203 | * Returns 0 on success, non-zero on failure. | |
204 | */ | |
205 | int anon_vma_fork(struct vm_area_struct *vma, struct vm_area_struct *pvma) | |
1da177e4 | 206 | { |
5beb4930 RR |
207 | struct anon_vma_chain *avc; |
208 | struct anon_vma *anon_vma; | |
1da177e4 | 209 | |
5beb4930 RR |
210 | /* Don't bother if the parent process has no anon_vma here. */ |
211 | if (!pvma->anon_vma) | |
212 | return 0; | |
213 | ||
214 | /* | |
215 | * First, attach the new VMA to the parent VMA's anon_vmas, | |
216 | * so rmap can find non-COWed pages in child processes. | |
217 | */ | |
218 | if (anon_vma_clone(vma, pvma)) | |
219 | return -ENOMEM; | |
220 | ||
221 | /* Then add our own anon_vma. */ | |
222 | anon_vma = anon_vma_alloc(); | |
223 | if (!anon_vma) | |
224 | goto out_error; | |
225 | avc = anon_vma_chain_alloc(); | |
226 | if (!avc) | |
227 | goto out_error_free_anon_vma; | |
228 | anon_vma_chain_link(vma, avc, anon_vma); | |
229 | /* Mark this anon_vma as the one where our new (COWed) pages go. */ | |
230 | vma->anon_vma = anon_vma; | |
231 | ||
232 | return 0; | |
233 | ||
234 | out_error_free_anon_vma: | |
235 | anon_vma_free(anon_vma); | |
236 | out_error: | |
4946d54c | 237 | unlink_anon_vmas(vma); |
5beb4930 | 238 | return -ENOMEM; |
1da177e4 LT |
239 | } |
240 | ||
5beb4930 | 241 | static void anon_vma_unlink(struct anon_vma_chain *anon_vma_chain) |
1da177e4 | 242 | { |
5beb4930 | 243 | struct anon_vma *anon_vma = anon_vma_chain->anon_vma; |
1da177e4 LT |
244 | int empty; |
245 | ||
5beb4930 | 246 | /* If anon_vma_fork fails, we can get an empty anon_vma_chain. */ |
1da177e4 LT |
247 | if (!anon_vma) |
248 | return; | |
249 | ||
250 | spin_lock(&anon_vma->lock); | |
5beb4930 | 251 | list_del(&anon_vma_chain->same_anon_vma); |
1da177e4 LT |
252 | |
253 | /* We must garbage collect the anon_vma if it's empty */ | |
7f60c214 | 254 | empty = list_empty(&anon_vma->head) && !anonvma_external_refcount(anon_vma); |
1da177e4 LT |
255 | spin_unlock(&anon_vma->lock); |
256 | ||
257 | if (empty) | |
258 | anon_vma_free(anon_vma); | |
259 | } | |
260 | ||
5beb4930 RR |
261 | void unlink_anon_vmas(struct vm_area_struct *vma) |
262 | { | |
263 | struct anon_vma_chain *avc, *next; | |
264 | ||
265 | /* Unlink each anon_vma chained to the VMA. */ | |
266 | list_for_each_entry_safe(avc, next, &vma->anon_vma_chain, same_vma) { | |
267 | anon_vma_unlink(avc); | |
268 | list_del(&avc->same_vma); | |
269 | anon_vma_chain_free(avc); | |
270 | } | |
271 | } | |
272 | ||
51cc5068 | 273 | static void anon_vma_ctor(void *data) |
1da177e4 | 274 | { |
a35afb83 | 275 | struct anon_vma *anon_vma = data; |
1da177e4 | 276 | |
a35afb83 | 277 | spin_lock_init(&anon_vma->lock); |
7f60c214 | 278 | anonvma_external_refcount_init(anon_vma); |
a35afb83 | 279 | INIT_LIST_HEAD(&anon_vma->head); |
1da177e4 LT |
280 | } |
281 | ||
282 | void __init anon_vma_init(void) | |
283 | { | |
284 | anon_vma_cachep = kmem_cache_create("anon_vma", sizeof(struct anon_vma), | |
20c2df83 | 285 | 0, SLAB_DESTROY_BY_RCU|SLAB_PANIC, anon_vma_ctor); |
5beb4930 | 286 | anon_vma_chain_cachep = KMEM_CACHE(anon_vma_chain, SLAB_PANIC); |
1da177e4 LT |
287 | } |
288 | ||
289 | /* | |
290 | * Getting a lock on a stable anon_vma from a page off the LRU is | |
291 | * tricky: page_lock_anon_vma rely on RCU to guard against the races. | |
292 | */ | |
10be22df | 293 | struct anon_vma *page_lock_anon_vma(struct page *page) |
1da177e4 | 294 | { |
34bbd704 | 295 | struct anon_vma *anon_vma; |
1da177e4 LT |
296 | unsigned long anon_mapping; |
297 | ||
298 | rcu_read_lock(); | |
80e14822 | 299 | anon_mapping = (unsigned long) ACCESS_ONCE(page->mapping); |
3ca7b3c5 | 300 | if ((anon_mapping & PAGE_MAPPING_FLAGS) != PAGE_MAPPING_ANON) |
1da177e4 LT |
301 | goto out; |
302 | if (!page_mapped(page)) | |
303 | goto out; | |
304 | ||
305 | anon_vma = (struct anon_vma *) (anon_mapping - PAGE_MAPPING_ANON); | |
306 | spin_lock(&anon_vma->lock); | |
34bbd704 | 307 | return anon_vma; |
1da177e4 LT |
308 | out: |
309 | rcu_read_unlock(); | |
34bbd704 ON |
310 | return NULL; |
311 | } | |
312 | ||
10be22df | 313 | void page_unlock_anon_vma(struct anon_vma *anon_vma) |
34bbd704 ON |
314 | { |
315 | spin_unlock(&anon_vma->lock); | |
316 | rcu_read_unlock(); | |
1da177e4 LT |
317 | } |
318 | ||
319 | /* | |
3ad33b24 LS |
320 | * At what user virtual address is page expected in @vma? |
321 | * Returns virtual address or -EFAULT if page's index/offset is not | |
322 | * within the range mapped the @vma. | |
1da177e4 LT |
323 | */ |
324 | static inline unsigned long | |
325 | vma_address(struct page *page, struct vm_area_struct *vma) | |
326 | { | |
327 | pgoff_t pgoff = page->index << (PAGE_CACHE_SHIFT - PAGE_SHIFT); | |
328 | unsigned long address; | |
329 | ||
0fe6e20b NH |
330 | if (unlikely(is_vm_hugetlb_page(vma))) |
331 | pgoff = page->index << huge_page_order(page_hstate(page)); | |
1da177e4 LT |
332 | address = vma->vm_start + ((pgoff - vma->vm_pgoff) << PAGE_SHIFT); |
333 | if (unlikely(address < vma->vm_start || address >= vma->vm_end)) { | |
3ad33b24 | 334 | /* page should be within @vma mapping range */ |
1da177e4 LT |
335 | return -EFAULT; |
336 | } | |
337 | return address; | |
338 | } | |
339 | ||
340 | /* | |
bf89c8c8 | 341 | * At what user virtual address is page expected in vma? |
ab941e0f | 342 | * Caller should check the page is actually part of the vma. |
1da177e4 LT |
343 | */ |
344 | unsigned long page_address_in_vma(struct page *page, struct vm_area_struct *vma) | |
345 | { | |
ab941e0f NH |
346 | if (PageAnon(page)) |
347 | ; | |
348 | else if (page->mapping && !(vma->vm_flags & VM_NONLINEAR)) { | |
ee498ed7 HD |
349 | if (!vma->vm_file || |
350 | vma->vm_file->f_mapping != page->mapping) | |
1da177e4 LT |
351 | return -EFAULT; |
352 | } else | |
353 | return -EFAULT; | |
354 | return vma_address(page, vma); | |
355 | } | |
356 | ||
81b4082d ND |
357 | /* |
358 | * Check that @page is mapped at @address into @mm. | |
359 | * | |
479db0bf NP |
360 | * If @sync is false, page_check_address may perform a racy check to avoid |
361 | * the page table lock when the pte is not present (helpful when reclaiming | |
362 | * highly shared pages). | |
363 | * | |
b8072f09 | 364 | * On success returns with pte mapped and locked. |
81b4082d | 365 | */ |
ceffc078 | 366 | pte_t *page_check_address(struct page *page, struct mm_struct *mm, |
479db0bf | 367 | unsigned long address, spinlock_t **ptlp, int sync) |
81b4082d ND |
368 | { |
369 | pgd_t *pgd; | |
370 | pud_t *pud; | |
371 | pmd_t *pmd; | |
372 | pte_t *pte; | |
c0718806 | 373 | spinlock_t *ptl; |
81b4082d | 374 | |
0fe6e20b NH |
375 | if (unlikely(PageHuge(page))) { |
376 | pte = huge_pte_offset(mm, address); | |
377 | ptl = &mm->page_table_lock; | |
378 | goto check; | |
379 | } | |
380 | ||
81b4082d | 381 | pgd = pgd_offset(mm, address); |
c0718806 HD |
382 | if (!pgd_present(*pgd)) |
383 | return NULL; | |
384 | ||
385 | pud = pud_offset(pgd, address); | |
386 | if (!pud_present(*pud)) | |
387 | return NULL; | |
388 | ||
389 | pmd = pmd_offset(pud, address); | |
390 | if (!pmd_present(*pmd)) | |
391 | return NULL; | |
392 | ||
393 | pte = pte_offset_map(pmd, address); | |
394 | /* Make a quick check before getting the lock */ | |
479db0bf | 395 | if (!sync && !pte_present(*pte)) { |
c0718806 HD |
396 | pte_unmap(pte); |
397 | return NULL; | |
398 | } | |
399 | ||
4c21e2f2 | 400 | ptl = pte_lockptr(mm, pmd); |
0fe6e20b | 401 | check: |
c0718806 HD |
402 | spin_lock(ptl); |
403 | if (pte_present(*pte) && page_to_pfn(page) == pte_pfn(*pte)) { | |
404 | *ptlp = ptl; | |
405 | return pte; | |
81b4082d | 406 | } |
c0718806 HD |
407 | pte_unmap_unlock(pte, ptl); |
408 | return NULL; | |
81b4082d ND |
409 | } |
410 | ||
b291f000 NP |
411 | /** |
412 | * page_mapped_in_vma - check whether a page is really mapped in a VMA | |
413 | * @page: the page to test | |
414 | * @vma: the VMA to test | |
415 | * | |
416 | * Returns 1 if the page is mapped into the page tables of the VMA, 0 | |
417 | * if the page is not mapped into the page tables of this VMA. Only | |
418 | * valid for normal file or anonymous VMAs. | |
419 | */ | |
6a46079c | 420 | int page_mapped_in_vma(struct page *page, struct vm_area_struct *vma) |
b291f000 NP |
421 | { |
422 | unsigned long address; | |
423 | pte_t *pte; | |
424 | spinlock_t *ptl; | |
425 | ||
426 | address = vma_address(page, vma); | |
427 | if (address == -EFAULT) /* out of vma range */ | |
428 | return 0; | |
429 | pte = page_check_address(page, vma->vm_mm, address, &ptl, 1); | |
430 | if (!pte) /* the page is not in this mm */ | |
431 | return 0; | |
432 | pte_unmap_unlock(pte, ptl); | |
433 | ||
434 | return 1; | |
435 | } | |
436 | ||
1da177e4 LT |
437 | /* |
438 | * Subfunctions of page_referenced: page_referenced_one called | |
439 | * repeatedly from either page_referenced_anon or page_referenced_file. | |
440 | */ | |
5ad64688 HD |
441 | int page_referenced_one(struct page *page, struct vm_area_struct *vma, |
442 | unsigned long address, unsigned int *mapcount, | |
443 | unsigned long *vm_flags) | |
1da177e4 LT |
444 | { |
445 | struct mm_struct *mm = vma->vm_mm; | |
1da177e4 | 446 | pte_t *pte; |
c0718806 | 447 | spinlock_t *ptl; |
1da177e4 LT |
448 | int referenced = 0; |
449 | ||
479db0bf | 450 | pte = page_check_address(page, mm, address, &ptl, 0); |
c0718806 HD |
451 | if (!pte) |
452 | goto out; | |
1da177e4 | 453 | |
b291f000 NP |
454 | /* |
455 | * Don't want to elevate referenced for mlocked page that gets this far, | |
456 | * in order that it progresses to try_to_unmap and is moved to the | |
457 | * unevictable list. | |
458 | */ | |
5a9bbdcd | 459 | if (vma->vm_flags & VM_LOCKED) { |
5a9bbdcd | 460 | *mapcount = 1; /* break early from loop */ |
03ef83af | 461 | *vm_flags |= VM_LOCKED; |
b291f000 NP |
462 | goto out_unmap; |
463 | } | |
464 | ||
4917e5d0 JW |
465 | if (ptep_clear_flush_young_notify(vma, address, pte)) { |
466 | /* | |
467 | * Don't treat a reference through a sequentially read | |
468 | * mapping as such. If the page has been used in | |
469 | * another mapping, we will catch it; if this other | |
470 | * mapping is already gone, the unmap path will have | |
471 | * set PG_referenced or activated the page. | |
472 | */ | |
473 | if (likely(!VM_SequentialReadHint(vma))) | |
474 | referenced++; | |
475 | } | |
1da177e4 | 476 | |
c0718806 HD |
477 | /* Pretend the page is referenced if the task has the |
478 | swap token and is in the middle of a page fault. */ | |
f7b7fd8f | 479 | if (mm != current->mm && has_swap_token(mm) && |
c0718806 HD |
480 | rwsem_is_locked(&mm->mmap_sem)) |
481 | referenced++; | |
482 | ||
b291f000 | 483 | out_unmap: |
c0718806 HD |
484 | (*mapcount)--; |
485 | pte_unmap_unlock(pte, ptl); | |
273f047e | 486 | |
6fe6b7e3 WF |
487 | if (referenced) |
488 | *vm_flags |= vma->vm_flags; | |
273f047e | 489 | out: |
1da177e4 LT |
490 | return referenced; |
491 | } | |
492 | ||
bed7161a | 493 | static int page_referenced_anon(struct page *page, |
6fe6b7e3 WF |
494 | struct mem_cgroup *mem_cont, |
495 | unsigned long *vm_flags) | |
1da177e4 LT |
496 | { |
497 | unsigned int mapcount; | |
498 | struct anon_vma *anon_vma; | |
5beb4930 | 499 | struct anon_vma_chain *avc; |
1da177e4 LT |
500 | int referenced = 0; |
501 | ||
502 | anon_vma = page_lock_anon_vma(page); | |
503 | if (!anon_vma) | |
504 | return referenced; | |
505 | ||
506 | mapcount = page_mapcount(page); | |
5beb4930 RR |
507 | list_for_each_entry(avc, &anon_vma->head, same_anon_vma) { |
508 | struct vm_area_struct *vma = avc->vma; | |
1cb1729b HD |
509 | unsigned long address = vma_address(page, vma); |
510 | if (address == -EFAULT) | |
511 | continue; | |
bed7161a BS |
512 | /* |
513 | * If we are reclaiming on behalf of a cgroup, skip | |
514 | * counting on behalf of references from different | |
515 | * cgroups | |
516 | */ | |
bd845e38 | 517 | if (mem_cont && !mm_match_cgroup(vma->vm_mm, mem_cont)) |
bed7161a | 518 | continue; |
1cb1729b | 519 | referenced += page_referenced_one(page, vma, address, |
6fe6b7e3 | 520 | &mapcount, vm_flags); |
1da177e4 LT |
521 | if (!mapcount) |
522 | break; | |
523 | } | |
34bbd704 ON |
524 | |
525 | page_unlock_anon_vma(anon_vma); | |
1da177e4 LT |
526 | return referenced; |
527 | } | |
528 | ||
529 | /** | |
530 | * page_referenced_file - referenced check for object-based rmap | |
531 | * @page: the page we're checking references on. | |
43d8eac4 | 532 | * @mem_cont: target memory controller |
6fe6b7e3 | 533 | * @vm_flags: collect encountered vma->vm_flags who actually referenced the page |
1da177e4 LT |
534 | * |
535 | * For an object-based mapped page, find all the places it is mapped and | |
536 | * check/clear the referenced flag. This is done by following the page->mapping | |
537 | * pointer, then walking the chain of vmas it holds. It returns the number | |
538 | * of references it found. | |
539 | * | |
540 | * This function is only called from page_referenced for object-based pages. | |
541 | */ | |
bed7161a | 542 | static int page_referenced_file(struct page *page, |
6fe6b7e3 WF |
543 | struct mem_cgroup *mem_cont, |
544 | unsigned long *vm_flags) | |
1da177e4 LT |
545 | { |
546 | unsigned int mapcount; | |
547 | struct address_space *mapping = page->mapping; | |
548 | pgoff_t pgoff = page->index << (PAGE_CACHE_SHIFT - PAGE_SHIFT); | |
549 | struct vm_area_struct *vma; | |
550 | struct prio_tree_iter iter; | |
551 | int referenced = 0; | |
552 | ||
553 | /* | |
554 | * The caller's checks on page->mapping and !PageAnon have made | |
555 | * sure that this is a file page: the check for page->mapping | |
556 | * excludes the case just before it gets set on an anon page. | |
557 | */ | |
558 | BUG_ON(PageAnon(page)); | |
559 | ||
560 | /* | |
561 | * The page lock not only makes sure that page->mapping cannot | |
562 | * suddenly be NULLified by truncation, it makes sure that the | |
563 | * structure at mapping cannot be freed and reused yet, | |
564 | * so we can safely take mapping->i_mmap_lock. | |
565 | */ | |
566 | BUG_ON(!PageLocked(page)); | |
567 | ||
568 | spin_lock(&mapping->i_mmap_lock); | |
569 | ||
570 | /* | |
571 | * i_mmap_lock does not stabilize mapcount at all, but mapcount | |
572 | * is more likely to be accurate if we note it after spinning. | |
573 | */ | |
574 | mapcount = page_mapcount(page); | |
575 | ||
576 | vma_prio_tree_foreach(vma, &iter, &mapping->i_mmap, pgoff, pgoff) { | |
1cb1729b HD |
577 | unsigned long address = vma_address(page, vma); |
578 | if (address == -EFAULT) | |
579 | continue; | |
bed7161a BS |
580 | /* |
581 | * If we are reclaiming on behalf of a cgroup, skip | |
582 | * counting on behalf of references from different | |
583 | * cgroups | |
584 | */ | |
bd845e38 | 585 | if (mem_cont && !mm_match_cgroup(vma->vm_mm, mem_cont)) |
bed7161a | 586 | continue; |
1cb1729b | 587 | referenced += page_referenced_one(page, vma, address, |
6fe6b7e3 | 588 | &mapcount, vm_flags); |
1da177e4 LT |
589 | if (!mapcount) |
590 | break; | |
591 | } | |
592 | ||
593 | spin_unlock(&mapping->i_mmap_lock); | |
594 | return referenced; | |
595 | } | |
596 | ||
597 | /** | |
598 | * page_referenced - test if the page was referenced | |
599 | * @page: the page to test | |
600 | * @is_locked: caller holds lock on the page | |
43d8eac4 | 601 | * @mem_cont: target memory controller |
6fe6b7e3 | 602 | * @vm_flags: collect encountered vma->vm_flags who actually referenced the page |
1da177e4 LT |
603 | * |
604 | * Quick test_and_clear_referenced for all mappings to a page, | |
605 | * returns the number of ptes which referenced the page. | |
606 | */ | |
6fe6b7e3 WF |
607 | int page_referenced(struct page *page, |
608 | int is_locked, | |
609 | struct mem_cgroup *mem_cont, | |
610 | unsigned long *vm_flags) | |
1da177e4 LT |
611 | { |
612 | int referenced = 0; | |
5ad64688 | 613 | int we_locked = 0; |
1da177e4 | 614 | |
6fe6b7e3 | 615 | *vm_flags = 0; |
3ca7b3c5 | 616 | if (page_mapped(page) && page_rmapping(page)) { |
5ad64688 HD |
617 | if (!is_locked && (!PageAnon(page) || PageKsm(page))) { |
618 | we_locked = trylock_page(page); | |
619 | if (!we_locked) { | |
620 | referenced++; | |
621 | goto out; | |
622 | } | |
623 | } | |
624 | if (unlikely(PageKsm(page))) | |
625 | referenced += page_referenced_ksm(page, mem_cont, | |
626 | vm_flags); | |
627 | else if (PageAnon(page)) | |
6fe6b7e3 WF |
628 | referenced += page_referenced_anon(page, mem_cont, |
629 | vm_flags); | |
5ad64688 | 630 | else if (page->mapping) |
6fe6b7e3 WF |
631 | referenced += page_referenced_file(page, mem_cont, |
632 | vm_flags); | |
5ad64688 | 633 | if (we_locked) |
1da177e4 | 634 | unlock_page(page); |
1da177e4 | 635 | } |
5ad64688 | 636 | out: |
5b7baf05 CB |
637 | if (page_test_and_clear_young(page)) |
638 | referenced++; | |
639 | ||
1da177e4 LT |
640 | return referenced; |
641 | } | |
642 | ||
1cb1729b HD |
643 | static int page_mkclean_one(struct page *page, struct vm_area_struct *vma, |
644 | unsigned long address) | |
d08b3851 PZ |
645 | { |
646 | struct mm_struct *mm = vma->vm_mm; | |
c2fda5fe | 647 | pte_t *pte; |
d08b3851 PZ |
648 | spinlock_t *ptl; |
649 | int ret = 0; | |
650 | ||
479db0bf | 651 | pte = page_check_address(page, mm, address, &ptl, 1); |
d08b3851 PZ |
652 | if (!pte) |
653 | goto out; | |
654 | ||
c2fda5fe PZ |
655 | if (pte_dirty(*pte) || pte_write(*pte)) { |
656 | pte_t entry; | |
d08b3851 | 657 | |
c2fda5fe | 658 | flush_cache_page(vma, address, pte_pfn(*pte)); |
cddb8a5c | 659 | entry = ptep_clear_flush_notify(vma, address, pte); |
c2fda5fe PZ |
660 | entry = pte_wrprotect(entry); |
661 | entry = pte_mkclean(entry); | |
d6e88e67 | 662 | set_pte_at(mm, address, pte, entry); |
c2fda5fe PZ |
663 | ret = 1; |
664 | } | |
d08b3851 | 665 | |
d08b3851 PZ |
666 | pte_unmap_unlock(pte, ptl); |
667 | out: | |
668 | return ret; | |
669 | } | |
670 | ||
671 | static int page_mkclean_file(struct address_space *mapping, struct page *page) | |
672 | { | |
673 | pgoff_t pgoff = page->index << (PAGE_CACHE_SHIFT - PAGE_SHIFT); | |
674 | struct vm_area_struct *vma; | |
675 | struct prio_tree_iter iter; | |
676 | int ret = 0; | |
677 | ||
678 | BUG_ON(PageAnon(page)); | |
679 | ||
680 | spin_lock(&mapping->i_mmap_lock); | |
681 | vma_prio_tree_foreach(vma, &iter, &mapping->i_mmap, pgoff, pgoff) { | |
1cb1729b HD |
682 | if (vma->vm_flags & VM_SHARED) { |
683 | unsigned long address = vma_address(page, vma); | |
684 | if (address == -EFAULT) | |
685 | continue; | |
686 | ret += page_mkclean_one(page, vma, address); | |
687 | } | |
d08b3851 PZ |
688 | } |
689 | spin_unlock(&mapping->i_mmap_lock); | |
690 | return ret; | |
691 | } | |
692 | ||
693 | int page_mkclean(struct page *page) | |
694 | { | |
695 | int ret = 0; | |
696 | ||
697 | BUG_ON(!PageLocked(page)); | |
698 | ||
699 | if (page_mapped(page)) { | |
700 | struct address_space *mapping = page_mapping(page); | |
ce7e9fae | 701 | if (mapping) { |
d08b3851 | 702 | ret = page_mkclean_file(mapping, page); |
ce7e9fae CB |
703 | if (page_test_dirty(page)) { |
704 | page_clear_dirty(page); | |
705 | ret = 1; | |
706 | } | |
6c210482 | 707 | } |
d08b3851 PZ |
708 | } |
709 | ||
710 | return ret; | |
711 | } | |
60b59bea | 712 | EXPORT_SYMBOL_GPL(page_mkclean); |
d08b3851 | 713 | |
c44b6743 RR |
714 | /** |
715 | * page_move_anon_rmap - move a page to our anon_vma | |
716 | * @page: the page to move to our anon_vma | |
717 | * @vma: the vma the page belongs to | |
718 | * @address: the user virtual address mapped | |
719 | * | |
720 | * When a page belongs exclusively to one process after a COW event, | |
721 | * that page can be moved into the anon_vma that belongs to just that | |
722 | * process, so the rmap code will not search the parent or sibling | |
723 | * processes. | |
724 | */ | |
725 | void page_move_anon_rmap(struct page *page, | |
726 | struct vm_area_struct *vma, unsigned long address) | |
727 | { | |
728 | struct anon_vma *anon_vma = vma->anon_vma; | |
729 | ||
730 | VM_BUG_ON(!PageLocked(page)); | |
731 | VM_BUG_ON(!anon_vma); | |
732 | VM_BUG_ON(page->index != linear_page_index(vma, address)); | |
733 | ||
734 | anon_vma = (void *) anon_vma + PAGE_MAPPING_ANON; | |
735 | page->mapping = (struct address_space *) anon_vma; | |
736 | } | |
737 | ||
9617d95e | 738 | /** |
43d8eac4 | 739 | * __page_set_anon_rmap - setup new anonymous rmap |
9617d95e NP |
740 | * @page: the page to add the mapping to |
741 | * @vma: the vm area in which the mapping is added | |
742 | * @address: the user virtual address mapped | |
e8a03feb | 743 | * @exclusive: the page is exclusively owned by the current process |
9617d95e NP |
744 | */ |
745 | static void __page_set_anon_rmap(struct page *page, | |
e8a03feb | 746 | struct vm_area_struct *vma, unsigned long address, int exclusive) |
9617d95e | 747 | { |
e8a03feb | 748 | struct anon_vma *anon_vma = vma->anon_vma; |
ea90002b | 749 | |
e8a03feb | 750 | BUG_ON(!anon_vma); |
ea90002b LT |
751 | |
752 | /* | |
e8a03feb RR |
753 | * If the page isn't exclusively mapped into this vma, |
754 | * we must use the _oldest_ possible anon_vma for the | |
755 | * page mapping! | |
ea90002b | 756 | * |
e8a03feb RR |
757 | * So take the last AVC chain entry in the vma, which is |
758 | * the deepest ancestor, and use the anon_vma from that. | |
ea90002b | 759 | */ |
e8a03feb RR |
760 | if (!exclusive) { |
761 | struct anon_vma_chain *avc; | |
762 | avc = list_entry(vma->anon_vma_chain.prev, struct anon_vma_chain, same_vma); | |
763 | anon_vma = avc->anon_vma; | |
764 | } | |
9617d95e | 765 | |
9617d95e NP |
766 | anon_vma = (void *) anon_vma + PAGE_MAPPING_ANON; |
767 | page->mapping = (struct address_space *) anon_vma; | |
9617d95e | 768 | page->index = linear_page_index(vma, address); |
9617d95e NP |
769 | } |
770 | ||
c97a9e10 | 771 | /** |
43d8eac4 | 772 | * __page_check_anon_rmap - sanity check anonymous rmap addition |
c97a9e10 NP |
773 | * @page: the page to add the mapping to |
774 | * @vma: the vm area in which the mapping is added | |
775 | * @address: the user virtual address mapped | |
776 | */ | |
777 | static void __page_check_anon_rmap(struct page *page, | |
778 | struct vm_area_struct *vma, unsigned long address) | |
779 | { | |
780 | #ifdef CONFIG_DEBUG_VM | |
781 | /* | |
782 | * The page's anon-rmap details (mapping and index) are guaranteed to | |
783 | * be set up correctly at this point. | |
784 | * | |
785 | * We have exclusion against page_add_anon_rmap because the caller | |
786 | * always holds the page locked, except if called from page_dup_rmap, | |
787 | * in which case the page is already known to be setup. | |
788 | * | |
789 | * We have exclusion against page_add_new_anon_rmap because those pages | |
790 | * are initially only visible via the pagetables, and the pte is locked | |
791 | * over the call to page_add_new_anon_rmap. | |
792 | */ | |
c97a9e10 NP |
793 | BUG_ON(page->index != linear_page_index(vma, address)); |
794 | #endif | |
795 | } | |
796 | ||
1da177e4 LT |
797 | /** |
798 | * page_add_anon_rmap - add pte mapping to an anonymous page | |
799 | * @page: the page to add the mapping to | |
800 | * @vma: the vm area in which the mapping is added | |
801 | * @address: the user virtual address mapped | |
802 | * | |
5ad64688 | 803 | * The caller needs to hold the pte lock, and the page must be locked in |
80e14822 HD |
804 | * the anon_vma case: to serialize mapping,index checking after setting, |
805 | * and to ensure that PageAnon is not being upgraded racily to PageKsm | |
806 | * (but PageKsm is never downgraded to PageAnon). | |
1da177e4 LT |
807 | */ |
808 | void page_add_anon_rmap(struct page *page, | |
809 | struct vm_area_struct *vma, unsigned long address) | |
810 | { | |
5ad64688 HD |
811 | int first = atomic_inc_and_test(&page->_mapcount); |
812 | if (first) | |
813 | __inc_zone_page_state(page, NR_ANON_PAGES); | |
814 | if (unlikely(PageKsm(page))) | |
815 | return; | |
816 | ||
c97a9e10 NP |
817 | VM_BUG_ON(!PageLocked(page)); |
818 | VM_BUG_ON(address < vma->vm_start || address >= vma->vm_end); | |
5ad64688 | 819 | if (first) |
e8a03feb | 820 | __page_set_anon_rmap(page, vma, address, 0); |
69029cd5 | 821 | else |
c97a9e10 | 822 | __page_check_anon_rmap(page, vma, address); |
1da177e4 LT |
823 | } |
824 | ||
43d8eac4 | 825 | /** |
9617d95e NP |
826 | * page_add_new_anon_rmap - add pte mapping to a new anonymous page |
827 | * @page: the page to add the mapping to | |
828 | * @vma: the vm area in which the mapping is added | |
829 | * @address: the user virtual address mapped | |
830 | * | |
831 | * Same as page_add_anon_rmap but must only be called on *new* pages. | |
832 | * This means the inc-and-test can be bypassed. | |
c97a9e10 | 833 | * Page does not have to be locked. |
9617d95e NP |
834 | */ |
835 | void page_add_new_anon_rmap(struct page *page, | |
836 | struct vm_area_struct *vma, unsigned long address) | |
837 | { | |
b5934c53 | 838 | VM_BUG_ON(address < vma->vm_start || address >= vma->vm_end); |
cbf84b7a HD |
839 | SetPageSwapBacked(page); |
840 | atomic_set(&page->_mapcount, 0); /* increment count (starts at -1) */ | |
5ad64688 | 841 | __inc_zone_page_state(page, NR_ANON_PAGES); |
e8a03feb | 842 | __page_set_anon_rmap(page, vma, address, 1); |
b5934c53 | 843 | if (page_evictable(page, vma)) |
cbf84b7a | 844 | lru_cache_add_lru(page, LRU_ACTIVE_ANON); |
b5934c53 HD |
845 | else |
846 | add_page_to_unevictable_list(page); | |
9617d95e NP |
847 | } |
848 | ||
1da177e4 LT |
849 | /** |
850 | * page_add_file_rmap - add pte mapping to a file page | |
851 | * @page: the page to add the mapping to | |
852 | * | |
b8072f09 | 853 | * The caller needs to hold the pte lock. |
1da177e4 LT |
854 | */ |
855 | void page_add_file_rmap(struct page *page) | |
856 | { | |
d69b042f | 857 | if (atomic_inc_and_test(&page->_mapcount)) { |
65ba55f5 | 858 | __inc_zone_page_state(page, NR_FILE_MAPPED); |
d8046582 | 859 | mem_cgroup_update_file_mapped(page, 1); |
d69b042f | 860 | } |
1da177e4 LT |
861 | } |
862 | ||
863 | /** | |
864 | * page_remove_rmap - take down pte mapping from a page | |
865 | * @page: page to remove mapping from | |
866 | * | |
b8072f09 | 867 | * The caller needs to hold the pte lock. |
1da177e4 | 868 | */ |
edc315fd | 869 | void page_remove_rmap(struct page *page) |
1da177e4 | 870 | { |
b904dcfe KM |
871 | /* page still mapped by someone else? */ |
872 | if (!atomic_add_negative(-1, &page->_mapcount)) | |
873 | return; | |
874 | ||
875 | /* | |
876 | * Now that the last pte has gone, s390 must transfer dirty | |
877 | * flag from storage key to struct page. We can usually skip | |
878 | * this if the page is anon, so about to be freed; but perhaps | |
879 | * not if it's in swapcache - there might be another pte slot | |
880 | * containing the swap entry, but page not yet written to swap. | |
881 | */ | |
882 | if ((!PageAnon(page) || PageSwapCache(page)) && page_test_dirty(page)) { | |
883 | page_clear_dirty(page); | |
884 | set_page_dirty(page); | |
1da177e4 | 885 | } |
0fe6e20b NH |
886 | /* |
887 | * Hugepages are not counted in NR_ANON_PAGES nor NR_FILE_MAPPED | |
888 | * and not charged by memcg for now. | |
889 | */ | |
890 | if (unlikely(PageHuge(page))) | |
891 | return; | |
b904dcfe KM |
892 | if (PageAnon(page)) { |
893 | mem_cgroup_uncharge_page(page); | |
894 | __dec_zone_page_state(page, NR_ANON_PAGES); | |
895 | } else { | |
896 | __dec_zone_page_state(page, NR_FILE_MAPPED); | |
d8046582 | 897 | mem_cgroup_update_file_mapped(page, -1); |
b904dcfe | 898 | } |
b904dcfe KM |
899 | /* |
900 | * It would be tidy to reset the PageAnon mapping here, | |
901 | * but that might overwrite a racing page_add_anon_rmap | |
902 | * which increments mapcount after us but sets mapping | |
903 | * before us: so leave the reset to free_hot_cold_page, | |
904 | * and remember that it's only reliable while mapped. | |
905 | * Leaving it set also helps swapoff to reinstate ptes | |
906 | * faster for those pages still in swapcache. | |
907 | */ | |
1da177e4 LT |
908 | } |
909 | ||
910 | /* | |
911 | * Subfunctions of try_to_unmap: try_to_unmap_one called | |
912 | * repeatedly from either try_to_unmap_anon or try_to_unmap_file. | |
913 | */ | |
5ad64688 HD |
914 | int try_to_unmap_one(struct page *page, struct vm_area_struct *vma, |
915 | unsigned long address, enum ttu_flags flags) | |
1da177e4 LT |
916 | { |
917 | struct mm_struct *mm = vma->vm_mm; | |
1da177e4 LT |
918 | pte_t *pte; |
919 | pte_t pteval; | |
c0718806 | 920 | spinlock_t *ptl; |
1da177e4 LT |
921 | int ret = SWAP_AGAIN; |
922 | ||
479db0bf | 923 | pte = page_check_address(page, mm, address, &ptl, 0); |
c0718806 | 924 | if (!pte) |
81b4082d | 925 | goto out; |
1da177e4 LT |
926 | |
927 | /* | |
928 | * If the page is mlock()d, we cannot swap it out. | |
929 | * If it's recently referenced (perhaps page_referenced | |
930 | * skipped over this mm) then we should reactivate it. | |
931 | */ | |
14fa31b8 | 932 | if (!(flags & TTU_IGNORE_MLOCK)) { |
caed0f48 KM |
933 | if (vma->vm_flags & VM_LOCKED) |
934 | goto out_mlock; | |
935 | ||
af8e3354 | 936 | if (TTU_ACTION(flags) == TTU_MUNLOCK) |
53f79acb | 937 | goto out_unmap; |
14fa31b8 AK |
938 | } |
939 | if (!(flags & TTU_IGNORE_ACCESS)) { | |
b291f000 NP |
940 | if (ptep_clear_flush_young_notify(vma, address, pte)) { |
941 | ret = SWAP_FAIL; | |
942 | goto out_unmap; | |
943 | } | |
944 | } | |
1da177e4 | 945 | |
1da177e4 LT |
946 | /* Nuke the page table entry. */ |
947 | flush_cache_page(vma, address, page_to_pfn(page)); | |
cddb8a5c | 948 | pteval = ptep_clear_flush_notify(vma, address, pte); |
1da177e4 LT |
949 | |
950 | /* Move the dirty bit to the physical page now the pte is gone. */ | |
951 | if (pte_dirty(pteval)) | |
952 | set_page_dirty(page); | |
953 | ||
365e9c87 HD |
954 | /* Update high watermark before we lower rss */ |
955 | update_hiwater_rss(mm); | |
956 | ||
888b9f7c AK |
957 | if (PageHWPoison(page) && !(flags & TTU_IGNORE_HWPOISON)) { |
958 | if (PageAnon(page)) | |
d559db08 | 959 | dec_mm_counter(mm, MM_ANONPAGES); |
888b9f7c | 960 | else |
d559db08 | 961 | dec_mm_counter(mm, MM_FILEPAGES); |
888b9f7c AK |
962 | set_pte_at(mm, address, pte, |
963 | swp_entry_to_pte(make_hwpoison_entry(page))); | |
964 | } else if (PageAnon(page)) { | |
4c21e2f2 | 965 | swp_entry_t entry = { .val = page_private(page) }; |
0697212a CL |
966 | |
967 | if (PageSwapCache(page)) { | |
968 | /* | |
969 | * Store the swap location in the pte. | |
970 | * See handle_pte_fault() ... | |
971 | */ | |
570a335b HD |
972 | if (swap_duplicate(entry) < 0) { |
973 | set_pte_at(mm, address, pte, pteval); | |
974 | ret = SWAP_FAIL; | |
975 | goto out_unmap; | |
976 | } | |
0697212a CL |
977 | if (list_empty(&mm->mmlist)) { |
978 | spin_lock(&mmlist_lock); | |
979 | if (list_empty(&mm->mmlist)) | |
980 | list_add(&mm->mmlist, &init_mm.mmlist); | |
981 | spin_unlock(&mmlist_lock); | |
982 | } | |
d559db08 | 983 | dec_mm_counter(mm, MM_ANONPAGES); |
b084d435 | 984 | inc_mm_counter(mm, MM_SWAPENTS); |
64cdd548 | 985 | } else if (PAGE_MIGRATION) { |
0697212a CL |
986 | /* |
987 | * Store the pfn of the page in a special migration | |
988 | * pte. do_swap_page() will wait until the migration | |
989 | * pte is removed and then restart fault handling. | |
990 | */ | |
14fa31b8 | 991 | BUG_ON(TTU_ACTION(flags) != TTU_MIGRATION); |
0697212a | 992 | entry = make_migration_entry(page, pte_write(pteval)); |
1da177e4 LT |
993 | } |
994 | set_pte_at(mm, address, pte, swp_entry_to_pte(entry)); | |
995 | BUG_ON(pte_file(*pte)); | |
14fa31b8 | 996 | } else if (PAGE_MIGRATION && (TTU_ACTION(flags) == TTU_MIGRATION)) { |
04e62a29 CL |
997 | /* Establish migration entry for a file page */ |
998 | swp_entry_t entry; | |
999 | entry = make_migration_entry(page, pte_write(pteval)); | |
1000 | set_pte_at(mm, address, pte, swp_entry_to_pte(entry)); | |
1001 | } else | |
d559db08 | 1002 | dec_mm_counter(mm, MM_FILEPAGES); |
1da177e4 | 1003 | |
edc315fd | 1004 | page_remove_rmap(page); |
1da177e4 LT |
1005 | page_cache_release(page); |
1006 | ||
1007 | out_unmap: | |
c0718806 | 1008 | pte_unmap_unlock(pte, ptl); |
caed0f48 KM |
1009 | out: |
1010 | return ret; | |
53f79acb | 1011 | |
caed0f48 KM |
1012 | out_mlock: |
1013 | pte_unmap_unlock(pte, ptl); | |
1014 | ||
1015 | ||
1016 | /* | |
1017 | * We need mmap_sem locking, Otherwise VM_LOCKED check makes | |
1018 | * unstable result and race. Plus, We can't wait here because | |
1019 | * we now hold anon_vma->lock or mapping->i_mmap_lock. | |
1020 | * if trylock failed, the page remain in evictable lru and later | |
1021 | * vmscan could retry to move the page to unevictable lru if the | |
1022 | * page is actually mlocked. | |
1023 | */ | |
1024 | if (down_read_trylock(&vma->vm_mm->mmap_sem)) { | |
1025 | if (vma->vm_flags & VM_LOCKED) { | |
1026 | mlock_vma_page(page); | |
1027 | ret = SWAP_MLOCK; | |
53f79acb | 1028 | } |
caed0f48 | 1029 | up_read(&vma->vm_mm->mmap_sem); |
53f79acb | 1030 | } |
1da177e4 LT |
1031 | return ret; |
1032 | } | |
1033 | ||
1034 | /* | |
1035 | * objrmap doesn't work for nonlinear VMAs because the assumption that | |
1036 | * offset-into-file correlates with offset-into-virtual-addresses does not hold. | |
1037 | * Consequently, given a particular page and its ->index, we cannot locate the | |
1038 | * ptes which are mapping that page without an exhaustive linear search. | |
1039 | * | |
1040 | * So what this code does is a mini "virtual scan" of each nonlinear VMA which | |
1041 | * maps the file to which the target page belongs. The ->vm_private_data field | |
1042 | * holds the current cursor into that scan. Successive searches will circulate | |
1043 | * around the vma's virtual address space. | |
1044 | * | |
1045 | * So as more replacement pressure is applied to the pages in a nonlinear VMA, | |
1046 | * more scanning pressure is placed against them as well. Eventually pages | |
1047 | * will become fully unmapped and are eligible for eviction. | |
1048 | * | |
1049 | * For very sparsely populated VMAs this is a little inefficient - chances are | |
1050 | * there there won't be many ptes located within the scan cluster. In this case | |
1051 | * maybe we could scan further - to the end of the pte page, perhaps. | |
b291f000 NP |
1052 | * |
1053 | * Mlocked pages: check VM_LOCKED under mmap_sem held for read, if we can | |
1054 | * acquire it without blocking. If vma locked, mlock the pages in the cluster, | |
1055 | * rather than unmapping them. If we encounter the "check_page" that vmscan is | |
1056 | * trying to unmap, return SWAP_MLOCK, else default SWAP_AGAIN. | |
1da177e4 LT |
1057 | */ |
1058 | #define CLUSTER_SIZE min(32*PAGE_SIZE, PMD_SIZE) | |
1059 | #define CLUSTER_MASK (~(CLUSTER_SIZE - 1)) | |
1060 | ||
b291f000 NP |
1061 | static int try_to_unmap_cluster(unsigned long cursor, unsigned int *mapcount, |
1062 | struct vm_area_struct *vma, struct page *check_page) | |
1da177e4 LT |
1063 | { |
1064 | struct mm_struct *mm = vma->vm_mm; | |
1065 | pgd_t *pgd; | |
1066 | pud_t *pud; | |
1067 | pmd_t *pmd; | |
c0718806 | 1068 | pte_t *pte; |
1da177e4 | 1069 | pte_t pteval; |
c0718806 | 1070 | spinlock_t *ptl; |
1da177e4 LT |
1071 | struct page *page; |
1072 | unsigned long address; | |
1073 | unsigned long end; | |
b291f000 NP |
1074 | int ret = SWAP_AGAIN; |
1075 | int locked_vma = 0; | |
1da177e4 | 1076 | |
1da177e4 LT |
1077 | address = (vma->vm_start + cursor) & CLUSTER_MASK; |
1078 | end = address + CLUSTER_SIZE; | |
1079 | if (address < vma->vm_start) | |
1080 | address = vma->vm_start; | |
1081 | if (end > vma->vm_end) | |
1082 | end = vma->vm_end; | |
1083 | ||
1084 | pgd = pgd_offset(mm, address); | |
1085 | if (!pgd_present(*pgd)) | |
b291f000 | 1086 | return ret; |
1da177e4 LT |
1087 | |
1088 | pud = pud_offset(pgd, address); | |
1089 | if (!pud_present(*pud)) | |
b291f000 | 1090 | return ret; |
1da177e4 LT |
1091 | |
1092 | pmd = pmd_offset(pud, address); | |
1093 | if (!pmd_present(*pmd)) | |
b291f000 NP |
1094 | return ret; |
1095 | ||
1096 | /* | |
af8e3354 | 1097 | * If we can acquire the mmap_sem for read, and vma is VM_LOCKED, |
b291f000 NP |
1098 | * keep the sem while scanning the cluster for mlocking pages. |
1099 | */ | |
af8e3354 | 1100 | if (down_read_trylock(&vma->vm_mm->mmap_sem)) { |
b291f000 NP |
1101 | locked_vma = (vma->vm_flags & VM_LOCKED); |
1102 | if (!locked_vma) | |
1103 | up_read(&vma->vm_mm->mmap_sem); /* don't need it */ | |
1104 | } | |
c0718806 HD |
1105 | |
1106 | pte = pte_offset_map_lock(mm, pmd, address, &ptl); | |
1da177e4 | 1107 | |
365e9c87 HD |
1108 | /* Update high watermark before we lower rss */ |
1109 | update_hiwater_rss(mm); | |
1110 | ||
c0718806 | 1111 | for (; address < end; pte++, address += PAGE_SIZE) { |
1da177e4 LT |
1112 | if (!pte_present(*pte)) |
1113 | continue; | |
6aab341e LT |
1114 | page = vm_normal_page(vma, address, *pte); |
1115 | BUG_ON(!page || PageAnon(page)); | |
1da177e4 | 1116 | |
b291f000 NP |
1117 | if (locked_vma) { |
1118 | mlock_vma_page(page); /* no-op if already mlocked */ | |
1119 | if (page == check_page) | |
1120 | ret = SWAP_MLOCK; | |
1121 | continue; /* don't unmap */ | |
1122 | } | |
1123 | ||
cddb8a5c | 1124 | if (ptep_clear_flush_young_notify(vma, address, pte)) |
1da177e4 LT |
1125 | continue; |
1126 | ||
1127 | /* Nuke the page table entry. */ | |
eca35133 | 1128 | flush_cache_page(vma, address, pte_pfn(*pte)); |
cddb8a5c | 1129 | pteval = ptep_clear_flush_notify(vma, address, pte); |
1da177e4 LT |
1130 | |
1131 | /* If nonlinear, store the file page offset in the pte. */ | |
1132 | if (page->index != linear_page_index(vma, address)) | |
1133 | set_pte_at(mm, address, pte, pgoff_to_pte(page->index)); | |
1134 | ||
1135 | /* Move the dirty bit to the physical page now the pte is gone. */ | |
1136 | if (pte_dirty(pteval)) | |
1137 | set_page_dirty(page); | |
1138 | ||
edc315fd | 1139 | page_remove_rmap(page); |
1da177e4 | 1140 | page_cache_release(page); |
d559db08 | 1141 | dec_mm_counter(mm, MM_FILEPAGES); |
1da177e4 LT |
1142 | (*mapcount)--; |
1143 | } | |
c0718806 | 1144 | pte_unmap_unlock(pte - 1, ptl); |
b291f000 NP |
1145 | if (locked_vma) |
1146 | up_read(&vma->vm_mm->mmap_sem); | |
1147 | return ret; | |
1da177e4 LT |
1148 | } |
1149 | ||
a8bef8ff MG |
1150 | static bool is_vma_temporary_stack(struct vm_area_struct *vma) |
1151 | { | |
1152 | int maybe_stack = vma->vm_flags & (VM_GROWSDOWN | VM_GROWSUP); | |
1153 | ||
1154 | if (!maybe_stack) | |
1155 | return false; | |
1156 | ||
1157 | if ((vma->vm_flags & VM_STACK_INCOMPLETE_SETUP) == | |
1158 | VM_STACK_INCOMPLETE_SETUP) | |
1159 | return true; | |
1160 | ||
1161 | return false; | |
1162 | } | |
1163 | ||
b291f000 NP |
1164 | /** |
1165 | * try_to_unmap_anon - unmap or unlock anonymous page using the object-based | |
1166 | * rmap method | |
1167 | * @page: the page to unmap/unlock | |
8051be5e | 1168 | * @flags: action and flags |
b291f000 NP |
1169 | * |
1170 | * Find all the mappings of a page using the mapping pointer and the vma chains | |
1171 | * contained in the anon_vma struct it points to. | |
1172 | * | |
1173 | * This function is only called from try_to_unmap/try_to_munlock for | |
1174 | * anonymous pages. | |
1175 | * When called from try_to_munlock(), the mmap_sem of the mm containing the vma | |
1176 | * where the page was found will be held for write. So, we won't recheck | |
1177 | * vm_flags for that VMA. That should be OK, because that vma shouldn't be | |
1178 | * 'LOCKED. | |
1179 | */ | |
14fa31b8 | 1180 | static int try_to_unmap_anon(struct page *page, enum ttu_flags flags) |
1da177e4 LT |
1181 | { |
1182 | struct anon_vma *anon_vma; | |
5beb4930 | 1183 | struct anon_vma_chain *avc; |
1da177e4 | 1184 | int ret = SWAP_AGAIN; |
b291f000 | 1185 | |
1da177e4 LT |
1186 | anon_vma = page_lock_anon_vma(page); |
1187 | if (!anon_vma) | |
1188 | return ret; | |
1189 | ||
5beb4930 RR |
1190 | list_for_each_entry(avc, &anon_vma->head, same_anon_vma) { |
1191 | struct vm_area_struct *vma = avc->vma; | |
a8bef8ff MG |
1192 | unsigned long address; |
1193 | ||
1194 | /* | |
1195 | * During exec, a temporary VMA is setup and later moved. | |
1196 | * The VMA is moved under the anon_vma lock but not the | |
1197 | * page tables leading to a race where migration cannot | |
1198 | * find the migration ptes. Rather than increasing the | |
1199 | * locking requirements of exec(), migration skips | |
1200 | * temporary VMAs until after exec() completes. | |
1201 | */ | |
1202 | if (PAGE_MIGRATION && (flags & TTU_MIGRATION) && | |
1203 | is_vma_temporary_stack(vma)) | |
1204 | continue; | |
1205 | ||
1206 | address = vma_address(page, vma); | |
1cb1729b HD |
1207 | if (address == -EFAULT) |
1208 | continue; | |
1209 | ret = try_to_unmap_one(page, vma, address, flags); | |
53f79acb HD |
1210 | if (ret != SWAP_AGAIN || !page_mapped(page)) |
1211 | break; | |
1da177e4 | 1212 | } |
34bbd704 ON |
1213 | |
1214 | page_unlock_anon_vma(anon_vma); | |
1da177e4 LT |
1215 | return ret; |
1216 | } | |
1217 | ||
1218 | /** | |
b291f000 NP |
1219 | * try_to_unmap_file - unmap/unlock file page using the object-based rmap method |
1220 | * @page: the page to unmap/unlock | |
14fa31b8 | 1221 | * @flags: action and flags |
1da177e4 LT |
1222 | * |
1223 | * Find all the mappings of a page using the mapping pointer and the vma chains | |
1224 | * contained in the address_space struct it points to. | |
1225 | * | |
b291f000 NP |
1226 | * This function is only called from try_to_unmap/try_to_munlock for |
1227 | * object-based pages. | |
1228 | * When called from try_to_munlock(), the mmap_sem of the mm containing the vma | |
1229 | * where the page was found will be held for write. So, we won't recheck | |
1230 | * vm_flags for that VMA. That should be OK, because that vma shouldn't be | |
1231 | * 'LOCKED. | |
1da177e4 | 1232 | */ |
14fa31b8 | 1233 | static int try_to_unmap_file(struct page *page, enum ttu_flags flags) |
1da177e4 LT |
1234 | { |
1235 | struct address_space *mapping = page->mapping; | |
1236 | pgoff_t pgoff = page->index << (PAGE_CACHE_SHIFT - PAGE_SHIFT); | |
1237 | struct vm_area_struct *vma; | |
1238 | struct prio_tree_iter iter; | |
1239 | int ret = SWAP_AGAIN; | |
1240 | unsigned long cursor; | |
1241 | unsigned long max_nl_cursor = 0; | |
1242 | unsigned long max_nl_size = 0; | |
1243 | unsigned int mapcount; | |
1244 | ||
1245 | spin_lock(&mapping->i_mmap_lock); | |
1246 | vma_prio_tree_foreach(vma, &iter, &mapping->i_mmap, pgoff, pgoff) { | |
1cb1729b HD |
1247 | unsigned long address = vma_address(page, vma); |
1248 | if (address == -EFAULT) | |
1249 | continue; | |
1250 | ret = try_to_unmap_one(page, vma, address, flags); | |
53f79acb HD |
1251 | if (ret != SWAP_AGAIN || !page_mapped(page)) |
1252 | goto out; | |
1da177e4 LT |
1253 | } |
1254 | ||
1255 | if (list_empty(&mapping->i_mmap_nonlinear)) | |
1256 | goto out; | |
1257 | ||
53f79acb HD |
1258 | /* |
1259 | * We don't bother to try to find the munlocked page in nonlinears. | |
1260 | * It's costly. Instead, later, page reclaim logic may call | |
1261 | * try_to_unmap(TTU_MUNLOCK) and recover PG_mlocked lazily. | |
1262 | */ | |
1263 | if (TTU_ACTION(flags) == TTU_MUNLOCK) | |
1264 | goto out; | |
1265 | ||
1da177e4 LT |
1266 | list_for_each_entry(vma, &mapping->i_mmap_nonlinear, |
1267 | shared.vm_set.list) { | |
1da177e4 LT |
1268 | cursor = (unsigned long) vma->vm_private_data; |
1269 | if (cursor > max_nl_cursor) | |
1270 | max_nl_cursor = cursor; | |
1271 | cursor = vma->vm_end - vma->vm_start; | |
1272 | if (cursor > max_nl_size) | |
1273 | max_nl_size = cursor; | |
1274 | } | |
1275 | ||
b291f000 | 1276 | if (max_nl_size == 0) { /* all nonlinears locked or reserved ? */ |
1da177e4 LT |
1277 | ret = SWAP_FAIL; |
1278 | goto out; | |
1279 | } | |
1280 | ||
1281 | /* | |
1282 | * We don't try to search for this page in the nonlinear vmas, | |
1283 | * and page_referenced wouldn't have found it anyway. Instead | |
1284 | * just walk the nonlinear vmas trying to age and unmap some. | |
1285 | * The mapcount of the page we came in with is irrelevant, | |
1286 | * but even so use it as a guide to how hard we should try? | |
1287 | */ | |
1288 | mapcount = page_mapcount(page); | |
1289 | if (!mapcount) | |
1290 | goto out; | |
1291 | cond_resched_lock(&mapping->i_mmap_lock); | |
1292 | ||
1293 | max_nl_size = (max_nl_size + CLUSTER_SIZE - 1) & CLUSTER_MASK; | |
1294 | if (max_nl_cursor == 0) | |
1295 | max_nl_cursor = CLUSTER_SIZE; | |
1296 | ||
1297 | do { | |
1298 | list_for_each_entry(vma, &mapping->i_mmap_nonlinear, | |
1299 | shared.vm_set.list) { | |
1da177e4 | 1300 | cursor = (unsigned long) vma->vm_private_data; |
839b9685 | 1301 | while ( cursor < max_nl_cursor && |
1da177e4 | 1302 | cursor < vma->vm_end - vma->vm_start) { |
53f79acb HD |
1303 | if (try_to_unmap_cluster(cursor, &mapcount, |
1304 | vma, page) == SWAP_MLOCK) | |
1305 | ret = SWAP_MLOCK; | |
1da177e4 LT |
1306 | cursor += CLUSTER_SIZE; |
1307 | vma->vm_private_data = (void *) cursor; | |
1308 | if ((int)mapcount <= 0) | |
1309 | goto out; | |
1310 | } | |
1311 | vma->vm_private_data = (void *) max_nl_cursor; | |
1312 | } | |
1313 | cond_resched_lock(&mapping->i_mmap_lock); | |
1314 | max_nl_cursor += CLUSTER_SIZE; | |
1315 | } while (max_nl_cursor <= max_nl_size); | |
1316 | ||
1317 | /* | |
1318 | * Don't loop forever (perhaps all the remaining pages are | |
1319 | * in locked vmas). Reset cursor on all unreserved nonlinear | |
1320 | * vmas, now forgetting on which ones it had fallen behind. | |
1321 | */ | |
101d2be7 HD |
1322 | list_for_each_entry(vma, &mapping->i_mmap_nonlinear, shared.vm_set.list) |
1323 | vma->vm_private_data = NULL; | |
1da177e4 LT |
1324 | out: |
1325 | spin_unlock(&mapping->i_mmap_lock); | |
1326 | return ret; | |
1327 | } | |
1328 | ||
1329 | /** | |
1330 | * try_to_unmap - try to remove all page table mappings to a page | |
1331 | * @page: the page to get unmapped | |
14fa31b8 | 1332 | * @flags: action and flags |
1da177e4 LT |
1333 | * |
1334 | * Tries to remove all the page table entries which are mapping this | |
1335 | * page, used in the pageout path. Caller must hold the page lock. | |
1336 | * Return values are: | |
1337 | * | |
1338 | * SWAP_SUCCESS - we succeeded in removing all mappings | |
1339 | * SWAP_AGAIN - we missed a mapping, try again later | |
1340 | * SWAP_FAIL - the page is unswappable | |
b291f000 | 1341 | * SWAP_MLOCK - page is mlocked. |
1da177e4 | 1342 | */ |
14fa31b8 | 1343 | int try_to_unmap(struct page *page, enum ttu_flags flags) |
1da177e4 LT |
1344 | { |
1345 | int ret; | |
1346 | ||
1da177e4 LT |
1347 | BUG_ON(!PageLocked(page)); |
1348 | ||
5ad64688 HD |
1349 | if (unlikely(PageKsm(page))) |
1350 | ret = try_to_unmap_ksm(page, flags); | |
1351 | else if (PageAnon(page)) | |
14fa31b8 | 1352 | ret = try_to_unmap_anon(page, flags); |
1da177e4 | 1353 | else |
14fa31b8 | 1354 | ret = try_to_unmap_file(page, flags); |
b291f000 | 1355 | if (ret != SWAP_MLOCK && !page_mapped(page)) |
1da177e4 LT |
1356 | ret = SWAP_SUCCESS; |
1357 | return ret; | |
1358 | } | |
81b4082d | 1359 | |
b291f000 NP |
1360 | /** |
1361 | * try_to_munlock - try to munlock a page | |
1362 | * @page: the page to be munlocked | |
1363 | * | |
1364 | * Called from munlock code. Checks all of the VMAs mapping the page | |
1365 | * to make sure nobody else has this page mlocked. The page will be | |
1366 | * returned with PG_mlocked cleared if no other vmas have it mlocked. | |
1367 | * | |
1368 | * Return values are: | |
1369 | * | |
53f79acb | 1370 | * SWAP_AGAIN - no vma is holding page mlocked, or, |
b291f000 | 1371 | * SWAP_AGAIN - page mapped in mlocked vma -- couldn't acquire mmap sem |
5ad64688 | 1372 | * SWAP_FAIL - page cannot be located at present |
b291f000 NP |
1373 | * SWAP_MLOCK - page is now mlocked. |
1374 | */ | |
1375 | int try_to_munlock(struct page *page) | |
1376 | { | |
1377 | VM_BUG_ON(!PageLocked(page) || PageLRU(page)); | |
1378 | ||
5ad64688 HD |
1379 | if (unlikely(PageKsm(page))) |
1380 | return try_to_unmap_ksm(page, TTU_MUNLOCK); | |
1381 | else if (PageAnon(page)) | |
14fa31b8 | 1382 | return try_to_unmap_anon(page, TTU_MUNLOCK); |
b291f000 | 1383 | else |
14fa31b8 | 1384 | return try_to_unmap_file(page, TTU_MUNLOCK); |
b291f000 | 1385 | } |
e9995ef9 HD |
1386 | |
1387 | #ifdef CONFIG_MIGRATION | |
1388 | /* | |
1389 | * rmap_walk() and its helpers rmap_walk_anon() and rmap_walk_file(): | |
1390 | * Called by migrate.c to remove migration ptes, but might be used more later. | |
1391 | */ | |
1392 | static int rmap_walk_anon(struct page *page, int (*rmap_one)(struct page *, | |
1393 | struct vm_area_struct *, unsigned long, void *), void *arg) | |
1394 | { | |
1395 | struct anon_vma *anon_vma; | |
5beb4930 | 1396 | struct anon_vma_chain *avc; |
e9995ef9 HD |
1397 | int ret = SWAP_AGAIN; |
1398 | ||
1399 | /* | |
1400 | * Note: remove_migration_ptes() cannot use page_lock_anon_vma() | |
1401 | * because that depends on page_mapped(); but not all its usages | |
3f6c8272 MG |
1402 | * are holding mmap_sem. Users without mmap_sem are required to |
1403 | * take a reference count to prevent the anon_vma disappearing | |
e9995ef9 HD |
1404 | */ |
1405 | anon_vma = page_anon_vma(page); | |
1406 | if (!anon_vma) | |
1407 | return ret; | |
1408 | spin_lock(&anon_vma->lock); | |
5beb4930 RR |
1409 | list_for_each_entry(avc, &anon_vma->head, same_anon_vma) { |
1410 | struct vm_area_struct *vma = avc->vma; | |
e9995ef9 HD |
1411 | unsigned long address = vma_address(page, vma); |
1412 | if (address == -EFAULT) | |
1413 | continue; | |
1414 | ret = rmap_one(page, vma, address, arg); | |
1415 | if (ret != SWAP_AGAIN) | |
1416 | break; | |
1417 | } | |
1418 | spin_unlock(&anon_vma->lock); | |
1419 | return ret; | |
1420 | } | |
1421 | ||
1422 | static int rmap_walk_file(struct page *page, int (*rmap_one)(struct page *, | |
1423 | struct vm_area_struct *, unsigned long, void *), void *arg) | |
1424 | { | |
1425 | struct address_space *mapping = page->mapping; | |
1426 | pgoff_t pgoff = page->index << (PAGE_CACHE_SHIFT - PAGE_SHIFT); | |
1427 | struct vm_area_struct *vma; | |
1428 | struct prio_tree_iter iter; | |
1429 | int ret = SWAP_AGAIN; | |
1430 | ||
1431 | if (!mapping) | |
1432 | return ret; | |
1433 | spin_lock(&mapping->i_mmap_lock); | |
1434 | vma_prio_tree_foreach(vma, &iter, &mapping->i_mmap, pgoff, pgoff) { | |
1435 | unsigned long address = vma_address(page, vma); | |
1436 | if (address == -EFAULT) | |
1437 | continue; | |
1438 | ret = rmap_one(page, vma, address, arg); | |
1439 | if (ret != SWAP_AGAIN) | |
1440 | break; | |
1441 | } | |
1442 | /* | |
1443 | * No nonlinear handling: being always shared, nonlinear vmas | |
1444 | * never contain migration ptes. Decide what to do about this | |
1445 | * limitation to linear when we need rmap_walk() on nonlinear. | |
1446 | */ | |
1447 | spin_unlock(&mapping->i_mmap_lock); | |
1448 | return ret; | |
1449 | } | |
1450 | ||
1451 | int rmap_walk(struct page *page, int (*rmap_one)(struct page *, | |
1452 | struct vm_area_struct *, unsigned long, void *), void *arg) | |
1453 | { | |
1454 | VM_BUG_ON(!PageLocked(page)); | |
1455 | ||
1456 | if (unlikely(PageKsm(page))) | |
1457 | return rmap_walk_ksm(page, rmap_one, arg); | |
1458 | else if (PageAnon(page)) | |
1459 | return rmap_walk_anon(page, rmap_one, arg); | |
1460 | else | |
1461 | return rmap_walk_file(page, rmap_one, arg); | |
1462 | } | |
1463 | #endif /* CONFIG_MIGRATION */ | |
0fe6e20b NH |
1464 | |
1465 | #ifdef CONFIG_HUGETLBFS | |
1466 | /* | |
1467 | * The following three functions are for anonymous (private mapped) hugepages. | |
1468 | * Unlike common anonymous pages, anonymous hugepages have no accounting code | |
1469 | * and no lru code, because we handle hugepages differently from common pages. | |
1470 | */ | |
1471 | static void __hugepage_set_anon_rmap(struct page *page, | |
1472 | struct vm_area_struct *vma, unsigned long address, int exclusive) | |
1473 | { | |
1474 | struct anon_vma *anon_vma = vma->anon_vma; | |
1475 | BUG_ON(!anon_vma); | |
1476 | if (!exclusive) { | |
1477 | struct anon_vma_chain *avc; | |
1478 | avc = list_entry(vma->anon_vma_chain.prev, | |
1479 | struct anon_vma_chain, same_vma); | |
1480 | anon_vma = avc->anon_vma; | |
1481 | } | |
1482 | anon_vma = (void *) anon_vma + PAGE_MAPPING_ANON; | |
1483 | page->mapping = (struct address_space *) anon_vma; | |
1484 | page->index = linear_page_index(vma, address); | |
1485 | } | |
1486 | ||
1487 | void hugepage_add_anon_rmap(struct page *page, | |
1488 | struct vm_area_struct *vma, unsigned long address) | |
1489 | { | |
1490 | struct anon_vma *anon_vma = vma->anon_vma; | |
1491 | int first; | |
1492 | BUG_ON(!anon_vma); | |
1493 | BUG_ON(address < vma->vm_start || address >= vma->vm_end); | |
1494 | first = atomic_inc_and_test(&page->_mapcount); | |
1495 | if (first) | |
1496 | __hugepage_set_anon_rmap(page, vma, address, 0); | |
1497 | } | |
1498 | ||
1499 | void hugepage_add_new_anon_rmap(struct page *page, | |
1500 | struct vm_area_struct *vma, unsigned long address) | |
1501 | { | |
1502 | BUG_ON(address < vma->vm_start || address >= vma->vm_end); | |
1503 | atomic_set(&page->_mapcount, 0); | |
1504 | __hugepage_set_anon_rmap(page, vma, address, 1); | |
1505 | } | |
1506 | #endif /* CONFIG_HUGETLBFS */ |