Commit | Line | Data |
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b20a3503 CL |
1 | /* |
2 | * Memory Migration functionality - linux/mm/migration.c | |
3 | * | |
4 | * Copyright (C) 2006 Silicon Graphics, Inc., Christoph Lameter | |
5 | * | |
6 | * Page migration was first developed in the context of the memory hotplug | |
7 | * project. The main authors of the migration code are: | |
8 | * | |
9 | * IWAMOTO Toshihiro <iwamoto@valinux.co.jp> | |
10 | * Hirokazu Takahashi <taka@valinux.co.jp> | |
11 | * Dave Hansen <haveblue@us.ibm.com> | |
12 | * Christoph Lameter <clameter@sgi.com> | |
13 | */ | |
14 | ||
15 | #include <linux/migrate.h> | |
16 | #include <linux/module.h> | |
17 | #include <linux/swap.h> | |
0697212a | 18 | #include <linux/swapops.h> |
b20a3503 | 19 | #include <linux/pagemap.h> |
e23ca00b | 20 | #include <linux/buffer_head.h> |
b20a3503 CL |
21 | #include <linux/mm_inline.h> |
22 | #include <linux/pagevec.h> | |
23 | #include <linux/rmap.h> | |
24 | #include <linux/topology.h> | |
25 | #include <linux/cpu.h> | |
26 | #include <linux/cpuset.h> | |
04e62a29 | 27 | #include <linux/writeback.h> |
742755a1 CL |
28 | #include <linux/mempolicy.h> |
29 | #include <linux/vmalloc.h> | |
86c3a764 | 30 | #include <linux/security.h> |
b20a3503 CL |
31 | |
32 | #include "internal.h" | |
33 | ||
b20a3503 CL |
34 | #define lru_to_page(_head) (list_entry((_head)->prev, struct page, lru)) |
35 | ||
36 | /* | |
37 | * Isolate one page from the LRU lists. If successful put it onto | |
38 | * the indicated list with elevated page count. | |
39 | * | |
40 | * Result: | |
41 | * -EBUSY: page not on LRU list | |
42 | * 0: page removed from LRU list and added to the specified list. | |
43 | */ | |
44 | int isolate_lru_page(struct page *page, struct list_head *pagelist) | |
45 | { | |
46 | int ret = -EBUSY; | |
47 | ||
48 | if (PageLRU(page)) { | |
49 | struct zone *zone = page_zone(page); | |
50 | ||
51 | spin_lock_irq(&zone->lru_lock); | |
52 | if (PageLRU(page)) { | |
53 | ret = 0; | |
54 | get_page(page); | |
55 | ClearPageLRU(page); | |
56 | if (PageActive(page)) | |
57 | del_page_from_active_list(zone, page); | |
58 | else | |
59 | del_page_from_inactive_list(zone, page); | |
60 | list_add_tail(&page->lru, pagelist); | |
61 | } | |
62 | spin_unlock_irq(&zone->lru_lock); | |
63 | } | |
64 | return ret; | |
65 | } | |
66 | ||
67 | /* | |
742755a1 CL |
68 | * migrate_prep() needs to be called before we start compiling a list of pages |
69 | * to be migrated using isolate_lru_page(). | |
b20a3503 CL |
70 | */ |
71 | int migrate_prep(void) | |
72 | { | |
b20a3503 CL |
73 | /* |
74 | * Clear the LRU lists so pages can be isolated. | |
75 | * Note that pages may be moved off the LRU after we have | |
76 | * drained them. Those pages will fail to migrate like other | |
77 | * pages that may be busy. | |
78 | */ | |
79 | lru_add_drain_all(); | |
80 | ||
81 | return 0; | |
82 | } | |
83 | ||
84 | static inline void move_to_lru(struct page *page) | |
85 | { | |
b20a3503 CL |
86 | if (PageActive(page)) { |
87 | /* | |
88 | * lru_cache_add_active checks that | |
89 | * the PG_active bit is off. | |
90 | */ | |
91 | ClearPageActive(page); | |
92 | lru_cache_add_active(page); | |
93 | } else { | |
94 | lru_cache_add(page); | |
95 | } | |
96 | put_page(page); | |
97 | } | |
98 | ||
99 | /* | |
100 | * Add isolated pages on the list back to the LRU. | |
101 | * | |
102 | * returns the number of pages put back. | |
103 | */ | |
104 | int putback_lru_pages(struct list_head *l) | |
105 | { | |
106 | struct page *page; | |
107 | struct page *page2; | |
108 | int count = 0; | |
109 | ||
110 | list_for_each_entry_safe(page, page2, l, lru) { | |
e24f0b8f | 111 | list_del(&page->lru); |
b20a3503 CL |
112 | move_to_lru(page); |
113 | count++; | |
114 | } | |
115 | return count; | |
116 | } | |
117 | ||
0697212a CL |
118 | static inline int is_swap_pte(pte_t pte) |
119 | { | |
120 | return !pte_none(pte) && !pte_present(pte) && !pte_file(pte); | |
121 | } | |
122 | ||
123 | /* | |
124 | * Restore a potential migration pte to a working pte entry | |
125 | */ | |
04e62a29 | 126 | static void remove_migration_pte(struct vm_area_struct *vma, |
0697212a CL |
127 | struct page *old, struct page *new) |
128 | { | |
129 | struct mm_struct *mm = vma->vm_mm; | |
130 | swp_entry_t entry; | |
131 | pgd_t *pgd; | |
132 | pud_t *pud; | |
133 | pmd_t *pmd; | |
134 | pte_t *ptep, pte; | |
135 | spinlock_t *ptl; | |
04e62a29 CL |
136 | unsigned long addr = page_address_in_vma(new, vma); |
137 | ||
138 | if (addr == -EFAULT) | |
139 | return; | |
0697212a CL |
140 | |
141 | pgd = pgd_offset(mm, addr); | |
142 | if (!pgd_present(*pgd)) | |
143 | return; | |
144 | ||
145 | pud = pud_offset(pgd, addr); | |
146 | if (!pud_present(*pud)) | |
147 | return; | |
148 | ||
149 | pmd = pmd_offset(pud, addr); | |
150 | if (!pmd_present(*pmd)) | |
151 | return; | |
152 | ||
153 | ptep = pte_offset_map(pmd, addr); | |
154 | ||
155 | if (!is_swap_pte(*ptep)) { | |
156 | pte_unmap(ptep); | |
157 | return; | |
158 | } | |
159 | ||
160 | ptl = pte_lockptr(mm, pmd); | |
161 | spin_lock(ptl); | |
162 | pte = *ptep; | |
163 | if (!is_swap_pte(pte)) | |
164 | goto out; | |
165 | ||
166 | entry = pte_to_swp_entry(pte); | |
167 | ||
168 | if (!is_migration_entry(entry) || migration_entry_to_page(entry) != old) | |
169 | goto out; | |
170 | ||
0697212a CL |
171 | get_page(new); |
172 | pte = pte_mkold(mk_pte(new, vma->vm_page_prot)); | |
173 | if (is_write_migration_entry(entry)) | |
174 | pte = pte_mkwrite(pte); | |
175 | set_pte_at(mm, addr, ptep, pte); | |
04e62a29 CL |
176 | |
177 | if (PageAnon(new)) | |
178 | page_add_anon_rmap(new, vma, addr); | |
179 | else | |
180 | page_add_file_rmap(new); | |
181 | ||
182 | /* No need to invalidate - it was non-present before */ | |
183 | update_mmu_cache(vma, addr, pte); | |
184 | lazy_mmu_prot_update(pte); | |
185 | ||
0697212a CL |
186 | out: |
187 | pte_unmap_unlock(ptep, ptl); | |
188 | } | |
189 | ||
190 | /* | |
04e62a29 CL |
191 | * Note that remove_file_migration_ptes will only work on regular mappings, |
192 | * Nonlinear mappings do not use migration entries. | |
193 | */ | |
194 | static void remove_file_migration_ptes(struct page *old, struct page *new) | |
195 | { | |
196 | struct vm_area_struct *vma; | |
197 | struct address_space *mapping = page_mapping(new); | |
198 | struct prio_tree_iter iter; | |
199 | pgoff_t pgoff = new->index << (PAGE_CACHE_SHIFT - PAGE_SHIFT); | |
200 | ||
201 | if (!mapping) | |
202 | return; | |
203 | ||
204 | spin_lock(&mapping->i_mmap_lock); | |
205 | ||
206 | vma_prio_tree_foreach(vma, &iter, &mapping->i_mmap, pgoff, pgoff) | |
207 | remove_migration_pte(vma, old, new); | |
208 | ||
209 | spin_unlock(&mapping->i_mmap_lock); | |
210 | } | |
211 | ||
212 | /* | |
0697212a CL |
213 | * Must hold mmap_sem lock on at least one of the vmas containing |
214 | * the page so that the anon_vma cannot vanish. | |
215 | */ | |
04e62a29 | 216 | static void remove_anon_migration_ptes(struct page *old, struct page *new) |
0697212a CL |
217 | { |
218 | struct anon_vma *anon_vma; | |
219 | struct vm_area_struct *vma; | |
220 | unsigned long mapping; | |
221 | ||
222 | mapping = (unsigned long)new->mapping; | |
223 | ||
224 | if (!mapping || (mapping & PAGE_MAPPING_ANON) == 0) | |
225 | return; | |
226 | ||
227 | /* | |
228 | * We hold the mmap_sem lock. So no need to call page_lock_anon_vma. | |
229 | */ | |
230 | anon_vma = (struct anon_vma *) (mapping - PAGE_MAPPING_ANON); | |
231 | spin_lock(&anon_vma->lock); | |
232 | ||
233 | list_for_each_entry(vma, &anon_vma->head, anon_vma_node) | |
04e62a29 | 234 | remove_migration_pte(vma, old, new); |
0697212a CL |
235 | |
236 | spin_unlock(&anon_vma->lock); | |
237 | } | |
238 | ||
04e62a29 CL |
239 | /* |
240 | * Get rid of all migration entries and replace them by | |
241 | * references to the indicated page. | |
242 | */ | |
243 | static void remove_migration_ptes(struct page *old, struct page *new) | |
244 | { | |
245 | if (PageAnon(new)) | |
246 | remove_anon_migration_ptes(old, new); | |
247 | else | |
248 | remove_file_migration_ptes(old, new); | |
249 | } | |
250 | ||
0697212a CL |
251 | /* |
252 | * Something used the pte of a page under migration. We need to | |
253 | * get to the page and wait until migration is finished. | |
254 | * When we return from this function the fault will be retried. | |
255 | * | |
256 | * This function is called from do_swap_page(). | |
257 | */ | |
258 | void migration_entry_wait(struct mm_struct *mm, pmd_t *pmd, | |
259 | unsigned long address) | |
260 | { | |
261 | pte_t *ptep, pte; | |
262 | spinlock_t *ptl; | |
263 | swp_entry_t entry; | |
264 | struct page *page; | |
265 | ||
266 | ptep = pte_offset_map_lock(mm, pmd, address, &ptl); | |
267 | pte = *ptep; | |
268 | if (!is_swap_pte(pte)) | |
269 | goto out; | |
270 | ||
271 | entry = pte_to_swp_entry(pte); | |
272 | if (!is_migration_entry(entry)) | |
273 | goto out; | |
274 | ||
275 | page = migration_entry_to_page(entry); | |
276 | ||
277 | get_page(page); | |
278 | pte_unmap_unlock(ptep, ptl); | |
279 | wait_on_page_locked(page); | |
280 | put_page(page); | |
281 | return; | |
282 | out: | |
283 | pte_unmap_unlock(ptep, ptl); | |
284 | } | |
285 | ||
b20a3503 | 286 | /* |
c3fcf8a5 | 287 | * Replace the page in the mapping. |
5b5c7120 CL |
288 | * |
289 | * The number of remaining references must be: | |
290 | * 1 for anonymous pages without a mapping | |
291 | * 2 for pages with a mapping | |
292 | * 3 for pages with a mapping and PagePrivate set. | |
b20a3503 | 293 | */ |
2d1db3b1 CL |
294 | static int migrate_page_move_mapping(struct address_space *mapping, |
295 | struct page *newpage, struct page *page) | |
b20a3503 | 296 | { |
b20a3503 CL |
297 | struct page **radix_pointer; |
298 | ||
6c5240ae CL |
299 | if (!mapping) { |
300 | /* Anonymous page */ | |
301 | if (page_count(page) != 1) | |
302 | return -EAGAIN; | |
303 | return 0; | |
304 | } | |
305 | ||
b20a3503 CL |
306 | write_lock_irq(&mapping->tree_lock); |
307 | ||
308 | radix_pointer = (struct page **)radix_tree_lookup_slot( | |
309 | &mapping->page_tree, | |
310 | page_index(page)); | |
311 | ||
6c5240ae | 312 | if (page_count(page) != 2 + !!PagePrivate(page) || |
b20a3503 CL |
313 | *radix_pointer != page) { |
314 | write_unlock_irq(&mapping->tree_lock); | |
e23ca00b | 315 | return -EAGAIN; |
b20a3503 CL |
316 | } |
317 | ||
318 | /* | |
319 | * Now we know that no one else is looking at the page. | |
b20a3503 CL |
320 | */ |
321 | get_page(newpage); | |
6c5240ae | 322 | #ifdef CONFIG_SWAP |
b20a3503 CL |
323 | if (PageSwapCache(page)) { |
324 | SetPageSwapCache(newpage); | |
325 | set_page_private(newpage, page_private(page)); | |
326 | } | |
6c5240ae | 327 | #endif |
b20a3503 CL |
328 | |
329 | *radix_pointer = newpage; | |
330 | __put_page(page); | |
331 | write_unlock_irq(&mapping->tree_lock); | |
332 | ||
333 | return 0; | |
334 | } | |
b20a3503 CL |
335 | |
336 | /* | |
337 | * Copy the page to its new location | |
338 | */ | |
e7340f73 | 339 | static void migrate_page_copy(struct page *newpage, struct page *page) |
b20a3503 CL |
340 | { |
341 | copy_highpage(newpage, page); | |
342 | ||
343 | if (PageError(page)) | |
344 | SetPageError(newpage); | |
345 | if (PageReferenced(page)) | |
346 | SetPageReferenced(newpage); | |
347 | if (PageUptodate(page)) | |
348 | SetPageUptodate(newpage); | |
349 | if (PageActive(page)) | |
350 | SetPageActive(newpage); | |
351 | if (PageChecked(page)) | |
352 | SetPageChecked(newpage); | |
353 | if (PageMappedToDisk(page)) | |
354 | SetPageMappedToDisk(newpage); | |
355 | ||
356 | if (PageDirty(page)) { | |
357 | clear_page_dirty_for_io(page); | |
358 | set_page_dirty(newpage); | |
359 | } | |
360 | ||
6c5240ae | 361 | #ifdef CONFIG_SWAP |
b20a3503 | 362 | ClearPageSwapCache(page); |
6c5240ae | 363 | #endif |
b20a3503 CL |
364 | ClearPageActive(page); |
365 | ClearPagePrivate(page); | |
366 | set_page_private(page, 0); | |
367 | page->mapping = NULL; | |
368 | ||
369 | /* | |
370 | * If any waiters have accumulated on the new page then | |
371 | * wake them up. | |
372 | */ | |
373 | if (PageWriteback(newpage)) | |
374 | end_page_writeback(newpage); | |
375 | } | |
b20a3503 | 376 | |
1d8b85cc CL |
377 | /************************************************************ |
378 | * Migration functions | |
379 | ***********************************************************/ | |
380 | ||
381 | /* Always fail migration. Used for mappings that are not movable */ | |
2d1db3b1 CL |
382 | int fail_migrate_page(struct address_space *mapping, |
383 | struct page *newpage, struct page *page) | |
1d8b85cc CL |
384 | { |
385 | return -EIO; | |
386 | } | |
387 | EXPORT_SYMBOL(fail_migrate_page); | |
388 | ||
b20a3503 CL |
389 | /* |
390 | * Common logic to directly migrate a single page suitable for | |
391 | * pages that do not use PagePrivate. | |
392 | * | |
393 | * Pages are locked upon entry and exit. | |
394 | */ | |
2d1db3b1 CL |
395 | int migrate_page(struct address_space *mapping, |
396 | struct page *newpage, struct page *page) | |
b20a3503 CL |
397 | { |
398 | int rc; | |
399 | ||
400 | BUG_ON(PageWriteback(page)); /* Writeback must be complete */ | |
401 | ||
2d1db3b1 | 402 | rc = migrate_page_move_mapping(mapping, newpage, page); |
b20a3503 CL |
403 | |
404 | if (rc) | |
405 | return rc; | |
406 | ||
407 | migrate_page_copy(newpage, page); | |
b20a3503 CL |
408 | return 0; |
409 | } | |
410 | EXPORT_SYMBOL(migrate_page); | |
411 | ||
9361401e | 412 | #ifdef CONFIG_BLOCK |
1d8b85cc CL |
413 | /* |
414 | * Migration function for pages with buffers. This function can only be used | |
415 | * if the underlying filesystem guarantees that no other references to "page" | |
416 | * exist. | |
417 | */ | |
2d1db3b1 CL |
418 | int buffer_migrate_page(struct address_space *mapping, |
419 | struct page *newpage, struct page *page) | |
1d8b85cc | 420 | { |
1d8b85cc CL |
421 | struct buffer_head *bh, *head; |
422 | int rc; | |
423 | ||
1d8b85cc | 424 | if (!page_has_buffers(page)) |
2d1db3b1 | 425 | return migrate_page(mapping, newpage, page); |
1d8b85cc CL |
426 | |
427 | head = page_buffers(page); | |
428 | ||
2d1db3b1 | 429 | rc = migrate_page_move_mapping(mapping, newpage, page); |
1d8b85cc CL |
430 | |
431 | if (rc) | |
432 | return rc; | |
433 | ||
434 | bh = head; | |
435 | do { | |
436 | get_bh(bh); | |
437 | lock_buffer(bh); | |
438 | bh = bh->b_this_page; | |
439 | ||
440 | } while (bh != head); | |
441 | ||
442 | ClearPagePrivate(page); | |
443 | set_page_private(newpage, page_private(page)); | |
444 | set_page_private(page, 0); | |
445 | put_page(page); | |
446 | get_page(newpage); | |
447 | ||
448 | bh = head; | |
449 | do { | |
450 | set_bh_page(bh, newpage, bh_offset(bh)); | |
451 | bh = bh->b_this_page; | |
452 | ||
453 | } while (bh != head); | |
454 | ||
455 | SetPagePrivate(newpage); | |
456 | ||
457 | migrate_page_copy(newpage, page); | |
458 | ||
459 | bh = head; | |
460 | do { | |
461 | unlock_buffer(bh); | |
462 | put_bh(bh); | |
463 | bh = bh->b_this_page; | |
464 | ||
465 | } while (bh != head); | |
466 | ||
467 | return 0; | |
468 | } | |
469 | EXPORT_SYMBOL(buffer_migrate_page); | |
9361401e | 470 | #endif |
1d8b85cc | 471 | |
04e62a29 CL |
472 | /* |
473 | * Writeback a page to clean the dirty state | |
474 | */ | |
475 | static int writeout(struct address_space *mapping, struct page *page) | |
8351a6e4 | 476 | { |
04e62a29 CL |
477 | struct writeback_control wbc = { |
478 | .sync_mode = WB_SYNC_NONE, | |
479 | .nr_to_write = 1, | |
480 | .range_start = 0, | |
481 | .range_end = LLONG_MAX, | |
482 | .nonblocking = 1, | |
483 | .for_reclaim = 1 | |
484 | }; | |
485 | int rc; | |
486 | ||
487 | if (!mapping->a_ops->writepage) | |
488 | /* No write method for the address space */ | |
489 | return -EINVAL; | |
490 | ||
491 | if (!clear_page_dirty_for_io(page)) | |
492 | /* Someone else already triggered a write */ | |
493 | return -EAGAIN; | |
494 | ||
8351a6e4 | 495 | /* |
04e62a29 CL |
496 | * A dirty page may imply that the underlying filesystem has |
497 | * the page on some queue. So the page must be clean for | |
498 | * migration. Writeout may mean we loose the lock and the | |
499 | * page state is no longer what we checked for earlier. | |
500 | * At this point we know that the migration attempt cannot | |
501 | * be successful. | |
8351a6e4 | 502 | */ |
04e62a29 | 503 | remove_migration_ptes(page, page); |
8351a6e4 | 504 | |
04e62a29 CL |
505 | rc = mapping->a_ops->writepage(page, &wbc); |
506 | if (rc < 0) | |
507 | /* I/O Error writing */ | |
508 | return -EIO; | |
8351a6e4 | 509 | |
04e62a29 CL |
510 | if (rc != AOP_WRITEPAGE_ACTIVATE) |
511 | /* unlocked. Relock */ | |
512 | lock_page(page); | |
513 | ||
514 | return -EAGAIN; | |
515 | } | |
516 | ||
517 | /* | |
518 | * Default handling if a filesystem does not provide a migration function. | |
519 | */ | |
520 | static int fallback_migrate_page(struct address_space *mapping, | |
521 | struct page *newpage, struct page *page) | |
522 | { | |
523 | if (PageDirty(page)) | |
524 | return writeout(mapping, page); | |
8351a6e4 CL |
525 | |
526 | /* | |
527 | * Buffers may be managed in a filesystem specific way. | |
528 | * We must have no buffers or drop them. | |
529 | */ | |
b398f6bf | 530 | if (PagePrivate(page) && |
8351a6e4 CL |
531 | !try_to_release_page(page, GFP_KERNEL)) |
532 | return -EAGAIN; | |
533 | ||
534 | return migrate_page(mapping, newpage, page); | |
535 | } | |
536 | ||
e24f0b8f CL |
537 | /* |
538 | * Move a page to a newly allocated page | |
539 | * The page is locked and all ptes have been successfully removed. | |
540 | * | |
541 | * The new page will have replaced the old page if this function | |
542 | * is successful. | |
543 | */ | |
544 | static int move_to_new_page(struct page *newpage, struct page *page) | |
545 | { | |
546 | struct address_space *mapping; | |
547 | int rc; | |
548 | ||
549 | /* | |
550 | * Block others from accessing the page when we get around to | |
551 | * establishing additional references. We are the only one | |
552 | * holding a reference to the new page at this point. | |
553 | */ | |
554 | if (TestSetPageLocked(newpage)) | |
555 | BUG(); | |
556 | ||
557 | /* Prepare mapping for the new page.*/ | |
558 | newpage->index = page->index; | |
559 | newpage->mapping = page->mapping; | |
560 | ||
561 | mapping = page_mapping(page); | |
562 | if (!mapping) | |
563 | rc = migrate_page(mapping, newpage, page); | |
564 | else if (mapping->a_ops->migratepage) | |
565 | /* | |
566 | * Most pages have a mapping and most filesystems | |
567 | * should provide a migration function. Anonymous | |
568 | * pages are part of swap space which also has its | |
569 | * own migration function. This is the most common | |
570 | * path for page migration. | |
571 | */ | |
572 | rc = mapping->a_ops->migratepage(mapping, | |
573 | newpage, page); | |
574 | else | |
575 | rc = fallback_migrate_page(mapping, newpage, page); | |
576 | ||
577 | if (!rc) | |
578 | remove_migration_ptes(page, newpage); | |
579 | else | |
580 | newpage->mapping = NULL; | |
581 | ||
582 | unlock_page(newpage); | |
583 | ||
584 | return rc; | |
585 | } | |
586 | ||
587 | /* | |
588 | * Obtain the lock on page, remove all ptes and migrate the page | |
589 | * to the newly allocated page in newpage. | |
590 | */ | |
95a402c3 CL |
591 | static int unmap_and_move(new_page_t get_new_page, unsigned long private, |
592 | struct page *page, int force) | |
e24f0b8f CL |
593 | { |
594 | int rc = 0; | |
742755a1 CL |
595 | int *result = NULL; |
596 | struct page *newpage = get_new_page(page, private, &result); | |
95a402c3 CL |
597 | |
598 | if (!newpage) | |
599 | return -ENOMEM; | |
e24f0b8f CL |
600 | |
601 | if (page_count(page) == 1) | |
602 | /* page was freed from under us. So we are done. */ | |
95a402c3 | 603 | goto move_newpage; |
e24f0b8f CL |
604 | |
605 | rc = -EAGAIN; | |
606 | if (TestSetPageLocked(page)) { | |
607 | if (!force) | |
95a402c3 | 608 | goto move_newpage; |
e24f0b8f CL |
609 | lock_page(page); |
610 | } | |
611 | ||
612 | if (PageWriteback(page)) { | |
613 | if (!force) | |
614 | goto unlock; | |
615 | wait_on_page_writeback(page); | |
616 | } | |
617 | ||
618 | /* | |
619 | * Establish migration ptes or remove ptes | |
620 | */ | |
e6a1530d CL |
621 | try_to_unmap(page, 1); |
622 | if (!page_mapped(page)) | |
623 | rc = move_to_new_page(newpage, page); | |
e24f0b8f CL |
624 | |
625 | if (rc) | |
626 | remove_migration_ptes(page, page); | |
e6a1530d | 627 | |
e24f0b8f CL |
628 | unlock: |
629 | unlock_page(page); | |
95a402c3 | 630 | |
e24f0b8f | 631 | if (rc != -EAGAIN) { |
aaa994b3 CL |
632 | /* |
633 | * A page that has been migrated has all references | |
634 | * removed and will be freed. A page that has not been | |
635 | * migrated will have kepts its references and be | |
636 | * restored. | |
637 | */ | |
638 | list_del(&page->lru); | |
639 | move_to_lru(page); | |
e24f0b8f | 640 | } |
95a402c3 CL |
641 | |
642 | move_newpage: | |
643 | /* | |
644 | * Move the new page to the LRU. If migration was not successful | |
645 | * then this will free the page. | |
646 | */ | |
647 | move_to_lru(newpage); | |
742755a1 CL |
648 | if (result) { |
649 | if (rc) | |
650 | *result = rc; | |
651 | else | |
652 | *result = page_to_nid(newpage); | |
653 | } | |
e24f0b8f CL |
654 | return rc; |
655 | } | |
656 | ||
b20a3503 CL |
657 | /* |
658 | * migrate_pages | |
659 | * | |
95a402c3 CL |
660 | * The function takes one list of pages to migrate and a function |
661 | * that determines from the page to be migrated and the private data | |
662 | * the target of the move and allocates the page. | |
b20a3503 CL |
663 | * |
664 | * The function returns after 10 attempts or if no pages | |
665 | * are movable anymore because to has become empty | |
aaa994b3 CL |
666 | * or no retryable pages exist anymore. All pages will be |
667 | * retruned to the LRU or freed. | |
b20a3503 | 668 | * |
95a402c3 | 669 | * Return: Number of pages not migrated or error code. |
b20a3503 | 670 | */ |
95a402c3 CL |
671 | int migrate_pages(struct list_head *from, |
672 | new_page_t get_new_page, unsigned long private) | |
b20a3503 | 673 | { |
e24f0b8f | 674 | int retry = 1; |
b20a3503 CL |
675 | int nr_failed = 0; |
676 | int pass = 0; | |
677 | struct page *page; | |
678 | struct page *page2; | |
679 | int swapwrite = current->flags & PF_SWAPWRITE; | |
680 | int rc; | |
681 | ||
682 | if (!swapwrite) | |
683 | current->flags |= PF_SWAPWRITE; | |
684 | ||
e24f0b8f CL |
685 | for(pass = 0; pass < 10 && retry; pass++) { |
686 | retry = 0; | |
b20a3503 | 687 | |
e24f0b8f | 688 | list_for_each_entry_safe(page, page2, from, lru) { |
e24f0b8f | 689 | cond_resched(); |
2d1db3b1 | 690 | |
95a402c3 CL |
691 | rc = unmap_and_move(get_new_page, private, |
692 | page, pass > 2); | |
2d1db3b1 | 693 | |
e24f0b8f | 694 | switch(rc) { |
95a402c3 CL |
695 | case -ENOMEM: |
696 | goto out; | |
e24f0b8f | 697 | case -EAGAIN: |
2d1db3b1 | 698 | retry++; |
e24f0b8f CL |
699 | break; |
700 | case 0: | |
e24f0b8f CL |
701 | break; |
702 | default: | |
2d1db3b1 | 703 | /* Permanent failure */ |
2d1db3b1 | 704 | nr_failed++; |
e24f0b8f | 705 | break; |
2d1db3b1 | 706 | } |
b20a3503 CL |
707 | } |
708 | } | |
95a402c3 CL |
709 | rc = 0; |
710 | out: | |
b20a3503 CL |
711 | if (!swapwrite) |
712 | current->flags &= ~PF_SWAPWRITE; | |
713 | ||
aaa994b3 | 714 | putback_lru_pages(from); |
b20a3503 | 715 | |
95a402c3 CL |
716 | if (rc) |
717 | return rc; | |
b20a3503 | 718 | |
95a402c3 | 719 | return nr_failed + retry; |
b20a3503 | 720 | } |
95a402c3 | 721 | |
742755a1 CL |
722 | #ifdef CONFIG_NUMA |
723 | /* | |
724 | * Move a list of individual pages | |
725 | */ | |
726 | struct page_to_node { | |
727 | unsigned long addr; | |
728 | struct page *page; | |
729 | int node; | |
730 | int status; | |
731 | }; | |
732 | ||
733 | static struct page *new_page_node(struct page *p, unsigned long private, | |
734 | int **result) | |
735 | { | |
736 | struct page_to_node *pm = (struct page_to_node *)private; | |
737 | ||
738 | while (pm->node != MAX_NUMNODES && pm->page != p) | |
739 | pm++; | |
740 | ||
741 | if (pm->node == MAX_NUMNODES) | |
742 | return NULL; | |
743 | ||
744 | *result = &pm->status; | |
745 | ||
980128f2 | 746 | return alloc_pages_node(pm->node, GFP_HIGHUSER | GFP_THISNODE, 0); |
742755a1 CL |
747 | } |
748 | ||
749 | /* | |
750 | * Move a set of pages as indicated in the pm array. The addr | |
751 | * field must be set to the virtual address of the page to be moved | |
752 | * and the node number must contain a valid target node. | |
753 | */ | |
754 | static int do_move_pages(struct mm_struct *mm, struct page_to_node *pm, | |
755 | int migrate_all) | |
756 | { | |
757 | int err; | |
758 | struct page_to_node *pp; | |
759 | LIST_HEAD(pagelist); | |
760 | ||
761 | down_read(&mm->mmap_sem); | |
762 | ||
763 | /* | |
764 | * Build a list of pages to migrate | |
765 | */ | |
766 | migrate_prep(); | |
767 | for (pp = pm; pp->node != MAX_NUMNODES; pp++) { | |
768 | struct vm_area_struct *vma; | |
769 | struct page *page; | |
770 | ||
771 | /* | |
772 | * A valid page pointer that will not match any of the | |
773 | * pages that will be moved. | |
774 | */ | |
775 | pp->page = ZERO_PAGE(0); | |
776 | ||
777 | err = -EFAULT; | |
778 | vma = find_vma(mm, pp->addr); | |
779 | if (!vma) | |
780 | goto set_status; | |
781 | ||
782 | page = follow_page(vma, pp->addr, FOLL_GET); | |
783 | err = -ENOENT; | |
784 | if (!page) | |
785 | goto set_status; | |
786 | ||
787 | if (PageReserved(page)) /* Check for zero page */ | |
788 | goto put_and_set; | |
789 | ||
790 | pp->page = page; | |
791 | err = page_to_nid(page); | |
792 | ||
793 | if (err == pp->node) | |
794 | /* | |
795 | * Node already in the right place | |
796 | */ | |
797 | goto put_and_set; | |
798 | ||
799 | err = -EACCES; | |
800 | if (page_mapcount(page) > 1 && | |
801 | !migrate_all) | |
802 | goto put_and_set; | |
803 | ||
804 | err = isolate_lru_page(page, &pagelist); | |
805 | put_and_set: | |
806 | /* | |
807 | * Either remove the duplicate refcount from | |
808 | * isolate_lru_page() or drop the page ref if it was | |
809 | * not isolated. | |
810 | */ | |
811 | put_page(page); | |
812 | set_status: | |
813 | pp->status = err; | |
814 | } | |
815 | ||
816 | if (!list_empty(&pagelist)) | |
817 | err = migrate_pages(&pagelist, new_page_node, | |
818 | (unsigned long)pm); | |
819 | else | |
820 | err = -ENOENT; | |
821 | ||
822 | up_read(&mm->mmap_sem); | |
823 | return err; | |
824 | } | |
825 | ||
826 | /* | |
827 | * Determine the nodes of a list of pages. The addr in the pm array | |
828 | * must have been set to the virtual address of which we want to determine | |
829 | * the node number. | |
830 | */ | |
831 | static int do_pages_stat(struct mm_struct *mm, struct page_to_node *pm) | |
832 | { | |
833 | down_read(&mm->mmap_sem); | |
834 | ||
835 | for ( ; pm->node != MAX_NUMNODES; pm++) { | |
836 | struct vm_area_struct *vma; | |
837 | struct page *page; | |
838 | int err; | |
839 | ||
840 | err = -EFAULT; | |
841 | vma = find_vma(mm, pm->addr); | |
842 | if (!vma) | |
843 | goto set_status; | |
844 | ||
845 | page = follow_page(vma, pm->addr, 0); | |
846 | err = -ENOENT; | |
847 | /* Use PageReserved to check for zero page */ | |
848 | if (!page || PageReserved(page)) | |
849 | goto set_status; | |
850 | ||
851 | err = page_to_nid(page); | |
852 | set_status: | |
853 | pm->status = err; | |
854 | } | |
855 | ||
856 | up_read(&mm->mmap_sem); | |
857 | return 0; | |
858 | } | |
859 | ||
860 | /* | |
861 | * Move a list of pages in the address space of the currently executing | |
862 | * process. | |
863 | */ | |
864 | asmlinkage long sys_move_pages(pid_t pid, unsigned long nr_pages, | |
865 | const void __user * __user *pages, | |
866 | const int __user *nodes, | |
867 | int __user *status, int flags) | |
868 | { | |
869 | int err = 0; | |
870 | int i; | |
871 | struct task_struct *task; | |
872 | nodemask_t task_nodes; | |
873 | struct mm_struct *mm; | |
874 | struct page_to_node *pm = NULL; | |
875 | ||
876 | /* Check flags */ | |
877 | if (flags & ~(MPOL_MF_MOVE|MPOL_MF_MOVE_ALL)) | |
878 | return -EINVAL; | |
879 | ||
880 | if ((flags & MPOL_MF_MOVE_ALL) && !capable(CAP_SYS_NICE)) | |
881 | return -EPERM; | |
882 | ||
883 | /* Find the mm_struct */ | |
884 | read_lock(&tasklist_lock); | |
885 | task = pid ? find_task_by_pid(pid) : current; | |
886 | if (!task) { | |
887 | read_unlock(&tasklist_lock); | |
888 | return -ESRCH; | |
889 | } | |
890 | mm = get_task_mm(task); | |
891 | read_unlock(&tasklist_lock); | |
892 | ||
893 | if (!mm) | |
894 | return -EINVAL; | |
895 | ||
896 | /* | |
897 | * Check if this process has the right to modify the specified | |
898 | * process. The right exists if the process has administrative | |
899 | * capabilities, superuser privileges or the same | |
900 | * userid as the target process. | |
901 | */ | |
902 | if ((current->euid != task->suid) && (current->euid != task->uid) && | |
903 | (current->uid != task->suid) && (current->uid != task->uid) && | |
904 | !capable(CAP_SYS_NICE)) { | |
905 | err = -EPERM; | |
906 | goto out2; | |
907 | } | |
908 | ||
86c3a764 DQ |
909 | err = security_task_movememory(task); |
910 | if (err) | |
911 | goto out2; | |
912 | ||
913 | ||
742755a1 CL |
914 | task_nodes = cpuset_mems_allowed(task); |
915 | ||
916 | /* Limit nr_pages so that the multiplication may not overflow */ | |
917 | if (nr_pages >= ULONG_MAX / sizeof(struct page_to_node) - 1) { | |
918 | err = -E2BIG; | |
919 | goto out2; | |
920 | } | |
921 | ||
922 | pm = vmalloc((nr_pages + 1) * sizeof(struct page_to_node)); | |
923 | if (!pm) { | |
924 | err = -ENOMEM; | |
925 | goto out2; | |
926 | } | |
927 | ||
928 | /* | |
929 | * Get parameters from user space and initialize the pm | |
930 | * array. Return various errors if the user did something wrong. | |
931 | */ | |
932 | for (i = 0; i < nr_pages; i++) { | |
933 | const void *p; | |
934 | ||
935 | err = -EFAULT; | |
936 | if (get_user(p, pages + i)) | |
937 | goto out; | |
938 | ||
939 | pm[i].addr = (unsigned long)p; | |
940 | if (nodes) { | |
941 | int node; | |
942 | ||
943 | if (get_user(node, nodes + i)) | |
944 | goto out; | |
945 | ||
946 | err = -ENODEV; | |
947 | if (!node_online(node)) | |
948 | goto out; | |
949 | ||
950 | err = -EACCES; | |
951 | if (!node_isset(node, task_nodes)) | |
952 | goto out; | |
953 | ||
954 | pm[i].node = node; | |
955 | } | |
956 | } | |
957 | /* End marker */ | |
958 | pm[nr_pages].node = MAX_NUMNODES; | |
959 | ||
960 | if (nodes) | |
961 | err = do_move_pages(mm, pm, flags & MPOL_MF_MOVE_ALL); | |
962 | else | |
963 | err = do_pages_stat(mm, pm); | |
964 | ||
965 | if (err >= 0) | |
966 | /* Return status information */ | |
967 | for (i = 0; i < nr_pages; i++) | |
968 | if (put_user(pm[i].status, status + i)) | |
969 | err = -EFAULT; | |
970 | ||
971 | out: | |
972 | vfree(pm); | |
973 | out2: | |
974 | mmput(mm); | |
975 | return err; | |
976 | } | |
977 | #endif | |
978 | ||
7b2259b3 CL |
979 | /* |
980 | * Call migration functions in the vma_ops that may prepare | |
981 | * memory in a vm for migration. migration functions may perform | |
982 | * the migration for vmas that do not have an underlying page struct. | |
983 | */ | |
984 | int migrate_vmas(struct mm_struct *mm, const nodemask_t *to, | |
985 | const nodemask_t *from, unsigned long flags) | |
986 | { | |
987 | struct vm_area_struct *vma; | |
988 | int err = 0; | |
989 | ||
990 | for(vma = mm->mmap; vma->vm_next && !err; vma = vma->vm_next) { | |
991 | if (vma->vm_ops && vma->vm_ops->migrate) { | |
992 | err = vma->vm_ops->migrate(vma, to, from, flags); | |
993 | if (err) | |
994 | break; | |
995 | } | |
996 | } | |
997 | return err; | |
998 | } |