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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> | |
cde53535 | 12 | * Christoph Lameter |
b20a3503 CL |
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 | 21 | #include <linux/mm_inline.h> |
b488893a | 22 | #include <linux/nsproxy.h> |
b20a3503 | 23 | #include <linux/pagevec.h> |
e9995ef9 | 24 | #include <linux/ksm.h> |
b20a3503 CL |
25 | #include <linux/rmap.h> |
26 | #include <linux/topology.h> | |
27 | #include <linux/cpu.h> | |
28 | #include <linux/cpuset.h> | |
04e62a29 | 29 | #include <linux/writeback.h> |
742755a1 CL |
30 | #include <linux/mempolicy.h> |
31 | #include <linux/vmalloc.h> | |
86c3a764 | 32 | #include <linux/security.h> |
8a9f3ccd | 33 | #include <linux/memcontrol.h> |
4f5ca265 | 34 | #include <linux/syscalls.h> |
290408d4 | 35 | #include <linux/hugetlb.h> |
5a0e3ad6 | 36 | #include <linux/gfp.h> |
b20a3503 CL |
37 | |
38 | #include "internal.h" | |
39 | ||
b20a3503 CL |
40 | #define lru_to_page(_head) (list_entry((_head)->prev, struct page, lru)) |
41 | ||
b20a3503 | 42 | /* |
742755a1 | 43 | * migrate_prep() needs to be called before we start compiling a list of pages |
748446bb MG |
44 | * to be migrated using isolate_lru_page(). If scheduling work on other CPUs is |
45 | * undesirable, use migrate_prep_local() | |
b20a3503 CL |
46 | */ |
47 | int migrate_prep(void) | |
48 | { | |
b20a3503 CL |
49 | /* |
50 | * Clear the LRU lists so pages can be isolated. | |
51 | * Note that pages may be moved off the LRU after we have | |
52 | * drained them. Those pages will fail to migrate like other | |
53 | * pages that may be busy. | |
54 | */ | |
55 | lru_add_drain_all(); | |
56 | ||
57 | return 0; | |
58 | } | |
59 | ||
748446bb MG |
60 | /* Do the necessary work of migrate_prep but not if it involves other CPUs */ |
61 | int migrate_prep_local(void) | |
62 | { | |
63 | lru_add_drain(); | |
64 | ||
65 | return 0; | |
66 | } | |
67 | ||
b20a3503 | 68 | /* |
894bc310 LS |
69 | * Add isolated pages on the list back to the LRU under page lock |
70 | * to avoid leaking evictable pages back onto unevictable list. | |
b20a3503 | 71 | */ |
e13861d8 | 72 | void putback_lru_pages(struct list_head *l) |
b20a3503 CL |
73 | { |
74 | struct page *page; | |
75 | struct page *page2; | |
b20a3503 CL |
76 | |
77 | list_for_each_entry_safe(page, page2, l, lru) { | |
e24f0b8f | 78 | list_del(&page->lru); |
a731286d | 79 | dec_zone_page_state(page, NR_ISOLATED_ANON + |
6c0b1351 | 80 | page_is_file_cache(page)); |
894bc310 | 81 | putback_lru_page(page); |
b20a3503 | 82 | } |
b20a3503 CL |
83 | } |
84 | ||
0697212a CL |
85 | /* |
86 | * Restore a potential migration pte to a working pte entry | |
87 | */ | |
e9995ef9 HD |
88 | static int remove_migration_pte(struct page *new, struct vm_area_struct *vma, |
89 | unsigned long addr, void *old) | |
0697212a CL |
90 | { |
91 | struct mm_struct *mm = vma->vm_mm; | |
92 | swp_entry_t entry; | |
93 | pgd_t *pgd; | |
94 | pud_t *pud; | |
95 | pmd_t *pmd; | |
96 | pte_t *ptep, pte; | |
97 | spinlock_t *ptl; | |
98 | ||
290408d4 NH |
99 | if (unlikely(PageHuge(new))) { |
100 | ptep = huge_pte_offset(mm, addr); | |
101 | if (!ptep) | |
102 | goto out; | |
103 | ptl = &mm->page_table_lock; | |
104 | } else { | |
105 | pgd = pgd_offset(mm, addr); | |
106 | if (!pgd_present(*pgd)) | |
107 | goto out; | |
0697212a | 108 | |
290408d4 NH |
109 | pud = pud_offset(pgd, addr); |
110 | if (!pud_present(*pud)) | |
111 | goto out; | |
0697212a | 112 | |
290408d4 NH |
113 | pmd = pmd_offset(pud, addr); |
114 | if (!pmd_present(*pmd)) | |
115 | goto out; | |
0697212a | 116 | |
290408d4 | 117 | ptep = pte_offset_map(pmd, addr); |
0697212a | 118 | |
290408d4 NH |
119 | if (!is_swap_pte(*ptep)) { |
120 | pte_unmap(ptep); | |
121 | goto out; | |
122 | } | |
123 | ||
124 | ptl = pte_lockptr(mm, pmd); | |
125 | } | |
0697212a | 126 | |
0697212a CL |
127 | spin_lock(ptl); |
128 | pte = *ptep; | |
129 | if (!is_swap_pte(pte)) | |
e9995ef9 | 130 | goto unlock; |
0697212a CL |
131 | |
132 | entry = pte_to_swp_entry(pte); | |
133 | ||
e9995ef9 HD |
134 | if (!is_migration_entry(entry) || |
135 | migration_entry_to_page(entry) != old) | |
136 | goto unlock; | |
0697212a | 137 | |
0697212a CL |
138 | get_page(new); |
139 | pte = pte_mkold(mk_pte(new, vma->vm_page_prot)); | |
140 | if (is_write_migration_entry(entry)) | |
141 | pte = pte_mkwrite(pte); | |
290408d4 NH |
142 | if (PageHuge(new)) |
143 | pte = pte_mkhuge(pte); | |
97ee0524 | 144 | flush_cache_page(vma, addr, pte_pfn(pte)); |
0697212a | 145 | set_pte_at(mm, addr, ptep, pte); |
04e62a29 | 146 | |
290408d4 NH |
147 | if (PageHuge(new)) { |
148 | if (PageAnon(new)) | |
149 | hugepage_add_anon_rmap(new, vma, addr); | |
150 | else | |
151 | page_dup_rmap(new); | |
152 | } else if (PageAnon(new)) | |
04e62a29 CL |
153 | page_add_anon_rmap(new, vma, addr); |
154 | else | |
155 | page_add_file_rmap(new); | |
156 | ||
157 | /* No need to invalidate - it was non-present before */ | |
4b3073e1 | 158 | update_mmu_cache(vma, addr, ptep); |
e9995ef9 | 159 | unlock: |
0697212a | 160 | pte_unmap_unlock(ptep, ptl); |
e9995ef9 HD |
161 | out: |
162 | return SWAP_AGAIN; | |
0697212a CL |
163 | } |
164 | ||
04e62a29 CL |
165 | /* |
166 | * Get rid of all migration entries and replace them by | |
167 | * references to the indicated page. | |
168 | */ | |
169 | static void remove_migration_ptes(struct page *old, struct page *new) | |
170 | { | |
e9995ef9 | 171 | rmap_walk(new, remove_migration_pte, old); |
04e62a29 CL |
172 | } |
173 | ||
0697212a CL |
174 | /* |
175 | * Something used the pte of a page under migration. We need to | |
176 | * get to the page and wait until migration is finished. | |
177 | * When we return from this function the fault will be retried. | |
178 | * | |
179 | * This function is called from do_swap_page(). | |
180 | */ | |
181 | void migration_entry_wait(struct mm_struct *mm, pmd_t *pmd, | |
182 | unsigned long address) | |
183 | { | |
184 | pte_t *ptep, pte; | |
185 | spinlock_t *ptl; | |
186 | swp_entry_t entry; | |
187 | struct page *page; | |
188 | ||
189 | ptep = pte_offset_map_lock(mm, pmd, address, &ptl); | |
190 | pte = *ptep; | |
191 | if (!is_swap_pte(pte)) | |
192 | goto out; | |
193 | ||
194 | entry = pte_to_swp_entry(pte); | |
195 | if (!is_migration_entry(entry)) | |
196 | goto out; | |
197 | ||
198 | page = migration_entry_to_page(entry); | |
199 | ||
e286781d NP |
200 | /* |
201 | * Once radix-tree replacement of page migration started, page_count | |
202 | * *must* be zero. And, we don't want to call wait_on_page_locked() | |
203 | * against a page without get_page(). | |
204 | * So, we use get_page_unless_zero(), here. Even failed, page fault | |
205 | * will occur again. | |
206 | */ | |
207 | if (!get_page_unless_zero(page)) | |
208 | goto out; | |
0697212a CL |
209 | pte_unmap_unlock(ptep, ptl); |
210 | wait_on_page_locked(page); | |
211 | put_page(page); | |
212 | return; | |
213 | out: | |
214 | pte_unmap_unlock(ptep, ptl); | |
215 | } | |
216 | ||
b20a3503 | 217 | /* |
c3fcf8a5 | 218 | * Replace the page in the mapping. |
5b5c7120 CL |
219 | * |
220 | * The number of remaining references must be: | |
221 | * 1 for anonymous pages without a mapping | |
222 | * 2 for pages with a mapping | |
266cf658 | 223 | * 3 for pages with a mapping and PagePrivate/PagePrivate2 set. |
b20a3503 | 224 | */ |
2d1db3b1 CL |
225 | static int migrate_page_move_mapping(struct address_space *mapping, |
226 | struct page *newpage, struct page *page) | |
b20a3503 | 227 | { |
e286781d | 228 | int expected_count; |
7cf9c2c7 | 229 | void **pslot; |
b20a3503 | 230 | |
6c5240ae | 231 | if (!mapping) { |
0e8c7d0f | 232 | /* Anonymous page without mapping */ |
6c5240ae CL |
233 | if (page_count(page) != 1) |
234 | return -EAGAIN; | |
235 | return 0; | |
236 | } | |
237 | ||
19fd6231 | 238 | spin_lock_irq(&mapping->tree_lock); |
b20a3503 | 239 | |
7cf9c2c7 NP |
240 | pslot = radix_tree_lookup_slot(&mapping->page_tree, |
241 | page_index(page)); | |
b20a3503 | 242 | |
edcf4748 | 243 | expected_count = 2 + page_has_private(page); |
e286781d | 244 | if (page_count(page) != expected_count || |
7cf9c2c7 | 245 | (struct page *)radix_tree_deref_slot(pslot) != page) { |
19fd6231 | 246 | spin_unlock_irq(&mapping->tree_lock); |
e23ca00b | 247 | return -EAGAIN; |
b20a3503 CL |
248 | } |
249 | ||
e286781d | 250 | if (!page_freeze_refs(page, expected_count)) { |
19fd6231 | 251 | spin_unlock_irq(&mapping->tree_lock); |
e286781d NP |
252 | return -EAGAIN; |
253 | } | |
254 | ||
b20a3503 CL |
255 | /* |
256 | * Now we know that no one else is looking at the page. | |
b20a3503 | 257 | */ |
7cf9c2c7 | 258 | get_page(newpage); /* add cache reference */ |
b20a3503 CL |
259 | if (PageSwapCache(page)) { |
260 | SetPageSwapCache(newpage); | |
261 | set_page_private(newpage, page_private(page)); | |
262 | } | |
263 | ||
7cf9c2c7 NP |
264 | radix_tree_replace_slot(pslot, newpage); |
265 | ||
e286781d | 266 | page_unfreeze_refs(page, expected_count); |
7cf9c2c7 NP |
267 | /* |
268 | * Drop cache reference from old page. | |
269 | * We know this isn't the last reference. | |
270 | */ | |
b20a3503 | 271 | __put_page(page); |
7cf9c2c7 | 272 | |
0e8c7d0f CL |
273 | /* |
274 | * If moved to a different zone then also account | |
275 | * the page for that zone. Other VM counters will be | |
276 | * taken care of when we establish references to the | |
277 | * new page and drop references to the old page. | |
278 | * | |
279 | * Note that anonymous pages are accounted for | |
280 | * via NR_FILE_PAGES and NR_ANON_PAGES if they | |
281 | * are mapped to swap space. | |
282 | */ | |
283 | __dec_zone_page_state(page, NR_FILE_PAGES); | |
284 | __inc_zone_page_state(newpage, NR_FILE_PAGES); | |
4b02108a KM |
285 | if (PageSwapBacked(page)) { |
286 | __dec_zone_page_state(page, NR_SHMEM); | |
287 | __inc_zone_page_state(newpage, NR_SHMEM); | |
288 | } | |
19fd6231 | 289 | spin_unlock_irq(&mapping->tree_lock); |
b20a3503 CL |
290 | |
291 | return 0; | |
292 | } | |
b20a3503 | 293 | |
290408d4 NH |
294 | /* |
295 | * The expected number of remaining references is the same as that | |
296 | * of migrate_page_move_mapping(). | |
297 | */ | |
298 | int migrate_huge_page_move_mapping(struct address_space *mapping, | |
299 | struct page *newpage, struct page *page) | |
300 | { | |
301 | int expected_count; | |
302 | void **pslot; | |
303 | ||
304 | if (!mapping) { | |
305 | if (page_count(page) != 1) | |
306 | return -EAGAIN; | |
307 | return 0; | |
308 | } | |
309 | ||
310 | spin_lock_irq(&mapping->tree_lock); | |
311 | ||
312 | pslot = radix_tree_lookup_slot(&mapping->page_tree, | |
313 | page_index(page)); | |
314 | ||
315 | expected_count = 2 + page_has_private(page); | |
316 | if (page_count(page) != expected_count || | |
317 | (struct page *)radix_tree_deref_slot(pslot) != page) { | |
318 | spin_unlock_irq(&mapping->tree_lock); | |
319 | return -EAGAIN; | |
320 | } | |
321 | ||
322 | if (!page_freeze_refs(page, expected_count)) { | |
323 | spin_unlock_irq(&mapping->tree_lock); | |
324 | return -EAGAIN; | |
325 | } | |
326 | ||
327 | get_page(newpage); | |
328 | ||
329 | radix_tree_replace_slot(pslot, newpage); | |
330 | ||
331 | page_unfreeze_refs(page, expected_count); | |
332 | ||
333 | __put_page(page); | |
334 | ||
335 | spin_unlock_irq(&mapping->tree_lock); | |
336 | return 0; | |
337 | } | |
338 | ||
b20a3503 CL |
339 | /* |
340 | * Copy the page to its new location | |
341 | */ | |
290408d4 | 342 | void migrate_page_copy(struct page *newpage, struct page *page) |
b20a3503 | 343 | { |
290408d4 NH |
344 | if (PageHuge(page)) |
345 | copy_huge_page(newpage, page); | |
346 | else | |
347 | copy_highpage(newpage, page); | |
b20a3503 CL |
348 | |
349 | if (PageError(page)) | |
350 | SetPageError(newpage); | |
351 | if (PageReferenced(page)) | |
352 | SetPageReferenced(newpage); | |
353 | if (PageUptodate(page)) | |
354 | SetPageUptodate(newpage); | |
894bc310 LS |
355 | if (TestClearPageActive(page)) { |
356 | VM_BUG_ON(PageUnevictable(page)); | |
b20a3503 | 357 | SetPageActive(newpage); |
418b27ef LS |
358 | } else if (TestClearPageUnevictable(page)) |
359 | SetPageUnevictable(newpage); | |
b20a3503 CL |
360 | if (PageChecked(page)) |
361 | SetPageChecked(newpage); | |
362 | if (PageMappedToDisk(page)) | |
363 | SetPageMappedToDisk(newpage); | |
364 | ||
365 | if (PageDirty(page)) { | |
366 | clear_page_dirty_for_io(page); | |
3a902c5f NP |
367 | /* |
368 | * Want to mark the page and the radix tree as dirty, and | |
369 | * redo the accounting that clear_page_dirty_for_io undid, | |
370 | * but we can't use set_page_dirty because that function | |
371 | * is actually a signal that all of the page has become dirty. | |
372 | * Wheras only part of our page may be dirty. | |
373 | */ | |
374 | __set_page_dirty_nobuffers(newpage); | |
b20a3503 CL |
375 | } |
376 | ||
b291f000 | 377 | mlock_migrate_page(newpage, page); |
e9995ef9 | 378 | ksm_migrate_page(newpage, page); |
b291f000 | 379 | |
b20a3503 | 380 | ClearPageSwapCache(page); |
b20a3503 CL |
381 | ClearPagePrivate(page); |
382 | set_page_private(page, 0); | |
383 | page->mapping = NULL; | |
384 | ||
385 | /* | |
386 | * If any waiters have accumulated on the new page then | |
387 | * wake them up. | |
388 | */ | |
389 | if (PageWriteback(newpage)) | |
390 | end_page_writeback(newpage); | |
391 | } | |
b20a3503 | 392 | |
1d8b85cc CL |
393 | /************************************************************ |
394 | * Migration functions | |
395 | ***********************************************************/ | |
396 | ||
397 | /* Always fail migration. Used for mappings that are not movable */ | |
2d1db3b1 CL |
398 | int fail_migrate_page(struct address_space *mapping, |
399 | struct page *newpage, struct page *page) | |
1d8b85cc CL |
400 | { |
401 | return -EIO; | |
402 | } | |
403 | EXPORT_SYMBOL(fail_migrate_page); | |
404 | ||
b20a3503 CL |
405 | /* |
406 | * Common logic to directly migrate a single page suitable for | |
266cf658 | 407 | * pages that do not use PagePrivate/PagePrivate2. |
b20a3503 CL |
408 | * |
409 | * Pages are locked upon entry and exit. | |
410 | */ | |
2d1db3b1 CL |
411 | int migrate_page(struct address_space *mapping, |
412 | struct page *newpage, struct page *page) | |
b20a3503 CL |
413 | { |
414 | int rc; | |
415 | ||
416 | BUG_ON(PageWriteback(page)); /* Writeback must be complete */ | |
417 | ||
2d1db3b1 | 418 | rc = migrate_page_move_mapping(mapping, newpage, page); |
b20a3503 CL |
419 | |
420 | if (rc) | |
421 | return rc; | |
422 | ||
423 | migrate_page_copy(newpage, page); | |
b20a3503 CL |
424 | return 0; |
425 | } | |
426 | EXPORT_SYMBOL(migrate_page); | |
427 | ||
9361401e | 428 | #ifdef CONFIG_BLOCK |
1d8b85cc CL |
429 | /* |
430 | * Migration function for pages with buffers. This function can only be used | |
431 | * if the underlying filesystem guarantees that no other references to "page" | |
432 | * exist. | |
433 | */ | |
2d1db3b1 CL |
434 | int buffer_migrate_page(struct address_space *mapping, |
435 | struct page *newpage, struct page *page) | |
1d8b85cc | 436 | { |
1d8b85cc CL |
437 | struct buffer_head *bh, *head; |
438 | int rc; | |
439 | ||
1d8b85cc | 440 | if (!page_has_buffers(page)) |
2d1db3b1 | 441 | return migrate_page(mapping, newpage, page); |
1d8b85cc CL |
442 | |
443 | head = page_buffers(page); | |
444 | ||
2d1db3b1 | 445 | rc = migrate_page_move_mapping(mapping, newpage, page); |
1d8b85cc CL |
446 | |
447 | if (rc) | |
448 | return rc; | |
449 | ||
450 | bh = head; | |
451 | do { | |
452 | get_bh(bh); | |
453 | lock_buffer(bh); | |
454 | bh = bh->b_this_page; | |
455 | ||
456 | } while (bh != head); | |
457 | ||
458 | ClearPagePrivate(page); | |
459 | set_page_private(newpage, page_private(page)); | |
460 | set_page_private(page, 0); | |
461 | put_page(page); | |
462 | get_page(newpage); | |
463 | ||
464 | bh = head; | |
465 | do { | |
466 | set_bh_page(bh, newpage, bh_offset(bh)); | |
467 | bh = bh->b_this_page; | |
468 | ||
469 | } while (bh != head); | |
470 | ||
471 | SetPagePrivate(newpage); | |
472 | ||
473 | migrate_page_copy(newpage, page); | |
474 | ||
475 | bh = head; | |
476 | do { | |
477 | unlock_buffer(bh); | |
478 | put_bh(bh); | |
479 | bh = bh->b_this_page; | |
480 | ||
481 | } while (bh != head); | |
482 | ||
483 | return 0; | |
484 | } | |
485 | EXPORT_SYMBOL(buffer_migrate_page); | |
9361401e | 486 | #endif |
1d8b85cc | 487 | |
04e62a29 CL |
488 | /* |
489 | * Writeback a page to clean the dirty state | |
490 | */ | |
491 | static int writeout(struct address_space *mapping, struct page *page) | |
8351a6e4 | 492 | { |
04e62a29 CL |
493 | struct writeback_control wbc = { |
494 | .sync_mode = WB_SYNC_NONE, | |
495 | .nr_to_write = 1, | |
496 | .range_start = 0, | |
497 | .range_end = LLONG_MAX, | |
498 | .nonblocking = 1, | |
499 | .for_reclaim = 1 | |
500 | }; | |
501 | int rc; | |
502 | ||
503 | if (!mapping->a_ops->writepage) | |
504 | /* No write method for the address space */ | |
505 | return -EINVAL; | |
506 | ||
507 | if (!clear_page_dirty_for_io(page)) | |
508 | /* Someone else already triggered a write */ | |
509 | return -EAGAIN; | |
510 | ||
8351a6e4 | 511 | /* |
04e62a29 CL |
512 | * A dirty page may imply that the underlying filesystem has |
513 | * the page on some queue. So the page must be clean for | |
514 | * migration. Writeout may mean we loose the lock and the | |
515 | * page state is no longer what we checked for earlier. | |
516 | * At this point we know that the migration attempt cannot | |
517 | * be successful. | |
8351a6e4 | 518 | */ |
04e62a29 | 519 | remove_migration_ptes(page, page); |
8351a6e4 | 520 | |
04e62a29 | 521 | rc = mapping->a_ops->writepage(page, &wbc); |
8351a6e4 | 522 | |
04e62a29 CL |
523 | if (rc != AOP_WRITEPAGE_ACTIVATE) |
524 | /* unlocked. Relock */ | |
525 | lock_page(page); | |
526 | ||
bda8550d | 527 | return (rc < 0) ? -EIO : -EAGAIN; |
04e62a29 CL |
528 | } |
529 | ||
530 | /* | |
531 | * Default handling if a filesystem does not provide a migration function. | |
532 | */ | |
533 | static int fallback_migrate_page(struct address_space *mapping, | |
534 | struct page *newpage, struct page *page) | |
535 | { | |
536 | if (PageDirty(page)) | |
537 | return writeout(mapping, page); | |
8351a6e4 CL |
538 | |
539 | /* | |
540 | * Buffers may be managed in a filesystem specific way. | |
541 | * We must have no buffers or drop them. | |
542 | */ | |
266cf658 | 543 | if (page_has_private(page) && |
8351a6e4 CL |
544 | !try_to_release_page(page, GFP_KERNEL)) |
545 | return -EAGAIN; | |
546 | ||
547 | return migrate_page(mapping, newpage, page); | |
548 | } | |
549 | ||
e24f0b8f CL |
550 | /* |
551 | * Move a page to a newly allocated page | |
552 | * The page is locked and all ptes have been successfully removed. | |
553 | * | |
554 | * The new page will have replaced the old page if this function | |
555 | * is successful. | |
894bc310 LS |
556 | * |
557 | * Return value: | |
558 | * < 0 - error code | |
559 | * == 0 - success | |
e24f0b8f | 560 | */ |
3fe2011f MG |
561 | static int move_to_new_page(struct page *newpage, struct page *page, |
562 | int remap_swapcache) | |
e24f0b8f CL |
563 | { |
564 | struct address_space *mapping; | |
565 | int rc; | |
566 | ||
567 | /* | |
568 | * Block others from accessing the page when we get around to | |
569 | * establishing additional references. We are the only one | |
570 | * holding a reference to the new page at this point. | |
571 | */ | |
529ae9aa | 572 | if (!trylock_page(newpage)) |
e24f0b8f CL |
573 | BUG(); |
574 | ||
575 | /* Prepare mapping for the new page.*/ | |
576 | newpage->index = page->index; | |
577 | newpage->mapping = page->mapping; | |
b2e18538 RR |
578 | if (PageSwapBacked(page)) |
579 | SetPageSwapBacked(newpage); | |
e24f0b8f CL |
580 | |
581 | mapping = page_mapping(page); | |
582 | if (!mapping) | |
583 | rc = migrate_page(mapping, newpage, page); | |
584 | else if (mapping->a_ops->migratepage) | |
585 | /* | |
586 | * Most pages have a mapping and most filesystems | |
587 | * should provide a migration function. Anonymous | |
588 | * pages are part of swap space which also has its | |
589 | * own migration function. This is the most common | |
590 | * path for page migration. | |
591 | */ | |
592 | rc = mapping->a_ops->migratepage(mapping, | |
593 | newpage, page); | |
594 | else | |
595 | rc = fallback_migrate_page(mapping, newpage, page); | |
596 | ||
3fe2011f | 597 | if (rc) { |
e24f0b8f | 598 | newpage->mapping = NULL; |
3fe2011f MG |
599 | } else { |
600 | if (remap_swapcache) | |
601 | remove_migration_ptes(page, newpage); | |
602 | } | |
e24f0b8f CL |
603 | |
604 | unlock_page(newpage); | |
605 | ||
606 | return rc; | |
607 | } | |
608 | ||
609 | /* | |
610 | * Obtain the lock on page, remove all ptes and migrate the page | |
611 | * to the newly allocated page in newpage. | |
612 | */ | |
95a402c3 | 613 | static int unmap_and_move(new_page_t get_new_page, unsigned long private, |
62b61f61 | 614 | struct page *page, int force, int offlining) |
e24f0b8f CL |
615 | { |
616 | int rc = 0; | |
742755a1 CL |
617 | int *result = NULL; |
618 | struct page *newpage = get_new_page(page, private, &result); | |
3fe2011f | 619 | int remap_swapcache = 1; |
989f89c5 | 620 | int rcu_locked = 0; |
ae41be37 | 621 | int charge = 0; |
e00e4316 | 622 | struct mem_cgroup *mem = NULL; |
3f6c8272 | 623 | struct anon_vma *anon_vma = NULL; |
95a402c3 CL |
624 | |
625 | if (!newpage) | |
626 | return -ENOMEM; | |
e24f0b8f | 627 | |
894bc310 | 628 | if (page_count(page) == 1) { |
e24f0b8f | 629 | /* page was freed from under us. So we are done. */ |
95a402c3 | 630 | goto move_newpage; |
894bc310 | 631 | } |
e24f0b8f | 632 | |
e8589cc1 | 633 | /* prepare cgroup just returns 0 or -ENOMEM */ |
e24f0b8f | 634 | rc = -EAGAIN; |
01b1ae63 | 635 | |
529ae9aa | 636 | if (!trylock_page(page)) { |
e24f0b8f | 637 | if (!force) |
95a402c3 | 638 | goto move_newpage; |
e24f0b8f CL |
639 | lock_page(page); |
640 | } | |
641 | ||
62b61f61 HD |
642 | /* |
643 | * Only memory hotplug's offline_pages() caller has locked out KSM, | |
644 | * and can safely migrate a KSM page. The other cases have skipped | |
645 | * PageKsm along with PageReserved - but it is only now when we have | |
646 | * the page lock that we can be certain it will not go KSM beneath us | |
647 | * (KSM will not upgrade a page from PageAnon to PageKsm when it sees | |
648 | * its pagecount raised, but only here do we take the page lock which | |
649 | * serializes that). | |
650 | */ | |
651 | if (PageKsm(page) && !offlining) { | |
652 | rc = -EBUSY; | |
653 | goto unlock; | |
654 | } | |
655 | ||
01b1ae63 | 656 | /* charge against new page */ |
ac39cf8c | 657 | charge = mem_cgroup_prepare_migration(page, newpage, &mem); |
01b1ae63 KH |
658 | if (charge == -ENOMEM) { |
659 | rc = -ENOMEM; | |
660 | goto unlock; | |
661 | } | |
662 | BUG_ON(charge); | |
663 | ||
e24f0b8f CL |
664 | if (PageWriteback(page)) { |
665 | if (!force) | |
01b1ae63 | 666 | goto uncharge; |
e24f0b8f CL |
667 | wait_on_page_writeback(page); |
668 | } | |
e24f0b8f | 669 | /* |
dc386d4d KH |
670 | * By try_to_unmap(), page->mapcount goes down to 0 here. In this case, |
671 | * we cannot notice that anon_vma is freed while we migrates a page. | |
672 | * This rcu_read_lock() delays freeing anon_vma pointer until the end | |
673 | * of migration. File cache pages are no problem because of page_lock() | |
989f89c5 KH |
674 | * File Caches may use write_page() or lock_page() in migration, then, |
675 | * just care Anon page here. | |
dc386d4d | 676 | */ |
989f89c5 KH |
677 | if (PageAnon(page)) { |
678 | rcu_read_lock(); | |
679 | rcu_locked = 1; | |
67b9509b | 680 | |
3fe2011f MG |
681 | /* Determine how to safely use anon_vma */ |
682 | if (!page_mapped(page)) { | |
683 | if (!PageSwapCache(page)) | |
684 | goto rcu_unlock; | |
67b9509b | 685 | |
3fe2011f MG |
686 | /* |
687 | * We cannot be sure that the anon_vma of an unmapped | |
688 | * swapcache page is safe to use because we don't | |
689 | * know in advance if the VMA that this page belonged | |
690 | * to still exists. If the VMA and others sharing the | |
691 | * data have been freed, then the anon_vma could | |
692 | * already be invalid. | |
693 | * | |
694 | * To avoid this possibility, swapcache pages get | |
695 | * migrated but are not remapped when migration | |
696 | * completes | |
697 | */ | |
698 | remap_swapcache = 0; | |
699 | } else { | |
700 | /* | |
701 | * Take a reference count on the anon_vma if the | |
702 | * page is mapped so that it is guaranteed to | |
703 | * exist when the page is remapped later | |
704 | */ | |
705 | anon_vma = page_anon_vma(page); | |
76545066 | 706 | get_anon_vma(anon_vma); |
3fe2011f | 707 | } |
989f89c5 | 708 | } |
62e1c553 | 709 | |
dc386d4d | 710 | /* |
62e1c553 SL |
711 | * Corner case handling: |
712 | * 1. When a new swap-cache page is read into, it is added to the LRU | |
713 | * and treated as swapcache but it has no rmap yet. | |
714 | * Calling try_to_unmap() against a page->mapping==NULL page will | |
715 | * trigger a BUG. So handle it here. | |
716 | * 2. An orphaned page (see truncate_complete_page) might have | |
717 | * fs-private metadata. The page can be picked up due to memory | |
718 | * offlining. Everywhere else except page reclaim, the page is | |
719 | * invisible to the vm, so the page can not be migrated. So try to | |
720 | * free the metadata, so the page can be freed. | |
e24f0b8f | 721 | */ |
62e1c553 | 722 | if (!page->mapping) { |
266cf658 | 723 | if (!PageAnon(page) && page_has_private(page)) { |
62e1c553 SL |
724 | /* |
725 | * Go direct to try_to_free_buffers() here because | |
726 | * a) that's what try_to_release_page() would do anyway | |
727 | * b) we may be under rcu_read_lock() here, so we can't | |
728 | * use GFP_KERNEL which is what try_to_release_page() | |
729 | * needs to be effective. | |
730 | */ | |
731 | try_to_free_buffers(page); | |
abfc3488 | 732 | goto rcu_unlock; |
62e1c553 | 733 | } |
abfc3488 | 734 | goto skip_unmap; |
62e1c553 SL |
735 | } |
736 | ||
dc386d4d | 737 | /* Establish migration ptes or remove ptes */ |
14fa31b8 | 738 | try_to_unmap(page, TTU_MIGRATION|TTU_IGNORE_MLOCK|TTU_IGNORE_ACCESS); |
dc386d4d | 739 | |
abfc3488 | 740 | skip_unmap: |
e6a1530d | 741 | if (!page_mapped(page)) |
3fe2011f | 742 | rc = move_to_new_page(newpage, page, remap_swapcache); |
e24f0b8f | 743 | |
3fe2011f | 744 | if (rc && remap_swapcache) |
e24f0b8f | 745 | remove_migration_ptes(page, page); |
dc386d4d | 746 | rcu_unlock: |
3f6c8272 MG |
747 | |
748 | /* Drop an anon_vma reference if we took one */ | |
76545066 RR |
749 | if (anon_vma) |
750 | drop_anon_vma(anon_vma); | |
3f6c8272 | 751 | |
989f89c5 KH |
752 | if (rcu_locked) |
753 | rcu_read_unlock(); | |
01b1ae63 KH |
754 | uncharge: |
755 | if (!charge) | |
756 | mem_cgroup_end_migration(mem, page, newpage); | |
e24f0b8f CL |
757 | unlock: |
758 | unlock_page(page); | |
95a402c3 | 759 | |
e24f0b8f | 760 | if (rc != -EAGAIN) { |
aaa994b3 CL |
761 | /* |
762 | * A page that has been migrated has all references | |
763 | * removed and will be freed. A page that has not been | |
764 | * migrated will have kepts its references and be | |
765 | * restored. | |
766 | */ | |
767 | list_del(&page->lru); | |
a731286d | 768 | dec_zone_page_state(page, NR_ISOLATED_ANON + |
6c0b1351 | 769 | page_is_file_cache(page)); |
894bc310 | 770 | putback_lru_page(page); |
e24f0b8f | 771 | } |
95a402c3 CL |
772 | |
773 | move_newpage: | |
894bc310 | 774 | |
95a402c3 CL |
775 | /* |
776 | * Move the new page to the LRU. If migration was not successful | |
777 | * then this will free the page. | |
778 | */ | |
894bc310 LS |
779 | putback_lru_page(newpage); |
780 | ||
742755a1 CL |
781 | if (result) { |
782 | if (rc) | |
783 | *result = rc; | |
784 | else | |
785 | *result = page_to_nid(newpage); | |
786 | } | |
e24f0b8f CL |
787 | return rc; |
788 | } | |
789 | ||
290408d4 NH |
790 | /* |
791 | * Counterpart of unmap_and_move_page() for hugepage migration. | |
792 | * | |
793 | * This function doesn't wait the completion of hugepage I/O | |
794 | * because there is no race between I/O and migration for hugepage. | |
795 | * Note that currently hugepage I/O occurs only in direct I/O | |
796 | * where no lock is held and PG_writeback is irrelevant, | |
797 | * and writeback status of all subpages are counted in the reference | |
798 | * count of the head page (i.e. if all subpages of a 2MB hugepage are | |
799 | * under direct I/O, the reference of the head page is 512 and a bit more.) | |
800 | * This means that when we try to migrate hugepage whose subpages are | |
801 | * doing direct I/O, some references remain after try_to_unmap() and | |
802 | * hugepage migration fails without data corruption. | |
803 | * | |
804 | * There is also no race when direct I/O is issued on the page under migration, | |
805 | * because then pte is replaced with migration swap entry and direct I/O code | |
806 | * will wait in the page fault for migration to complete. | |
807 | */ | |
808 | static int unmap_and_move_huge_page(new_page_t get_new_page, | |
809 | unsigned long private, struct page *hpage, | |
810 | int force, int offlining) | |
811 | { | |
812 | int rc = 0; | |
813 | int *result = NULL; | |
814 | struct page *new_hpage = get_new_page(hpage, private, &result); | |
815 | int rcu_locked = 0; | |
816 | struct anon_vma *anon_vma = NULL; | |
817 | ||
818 | if (!new_hpage) | |
819 | return -ENOMEM; | |
820 | ||
821 | rc = -EAGAIN; | |
822 | ||
823 | if (!trylock_page(hpage)) { | |
824 | if (!force) | |
825 | goto out; | |
826 | lock_page(hpage); | |
827 | } | |
828 | ||
829 | if (PageAnon(hpage)) { | |
830 | rcu_read_lock(); | |
831 | rcu_locked = 1; | |
832 | ||
833 | if (page_mapped(hpage)) { | |
834 | anon_vma = page_anon_vma(hpage); | |
835 | atomic_inc(&anon_vma->external_refcount); | |
836 | } | |
837 | } | |
838 | ||
839 | try_to_unmap(hpage, TTU_MIGRATION|TTU_IGNORE_MLOCK|TTU_IGNORE_ACCESS); | |
840 | ||
841 | if (!page_mapped(hpage)) | |
842 | rc = move_to_new_page(new_hpage, hpage, 1); | |
843 | ||
844 | if (rc) | |
845 | remove_migration_ptes(hpage, hpage); | |
846 | ||
847 | if (anon_vma && atomic_dec_and_lock(&anon_vma->external_refcount, | |
848 | &anon_vma->lock)) { | |
849 | int empty = list_empty(&anon_vma->head); | |
850 | spin_unlock(&anon_vma->lock); | |
851 | if (empty) | |
852 | anon_vma_free(anon_vma); | |
853 | } | |
854 | ||
855 | if (rcu_locked) | |
856 | rcu_read_unlock(); | |
857 | out: | |
858 | unlock_page(hpage); | |
859 | ||
860 | if (rc != -EAGAIN) { | |
861 | list_del(&hpage->lru); | |
862 | put_page(hpage); | |
863 | } | |
864 | ||
865 | put_page(new_hpage); | |
866 | ||
867 | if (result) { | |
868 | if (rc) | |
869 | *result = rc; | |
870 | else | |
871 | *result = page_to_nid(new_hpage); | |
872 | } | |
873 | return rc; | |
874 | } | |
875 | ||
b20a3503 CL |
876 | /* |
877 | * migrate_pages | |
878 | * | |
95a402c3 CL |
879 | * The function takes one list of pages to migrate and a function |
880 | * that determines from the page to be migrated and the private data | |
881 | * the target of the move and allocates the page. | |
b20a3503 CL |
882 | * |
883 | * The function returns after 10 attempts or if no pages | |
884 | * are movable anymore because to has become empty | |
aaa994b3 | 885 | * or no retryable pages exist anymore. All pages will be |
e9534b3f | 886 | * returned to the LRU or freed. |
b20a3503 | 887 | * |
95a402c3 | 888 | * Return: Number of pages not migrated or error code. |
b20a3503 | 889 | */ |
95a402c3 | 890 | int migrate_pages(struct list_head *from, |
62b61f61 | 891 | new_page_t get_new_page, unsigned long private, int offlining) |
b20a3503 | 892 | { |
e24f0b8f | 893 | int retry = 1; |
b20a3503 CL |
894 | int nr_failed = 0; |
895 | int pass = 0; | |
896 | struct page *page; | |
897 | struct page *page2; | |
898 | int swapwrite = current->flags & PF_SWAPWRITE; | |
899 | int rc; | |
900 | ||
901 | if (!swapwrite) | |
902 | current->flags |= PF_SWAPWRITE; | |
903 | ||
e24f0b8f CL |
904 | for(pass = 0; pass < 10 && retry; pass++) { |
905 | retry = 0; | |
b20a3503 | 906 | |
e24f0b8f | 907 | list_for_each_entry_safe(page, page2, from, lru) { |
e24f0b8f | 908 | cond_resched(); |
2d1db3b1 | 909 | |
95a402c3 | 910 | rc = unmap_and_move(get_new_page, private, |
62b61f61 | 911 | page, pass > 2, offlining); |
2d1db3b1 | 912 | |
e24f0b8f | 913 | switch(rc) { |
95a402c3 CL |
914 | case -ENOMEM: |
915 | goto out; | |
e24f0b8f | 916 | case -EAGAIN: |
2d1db3b1 | 917 | retry++; |
e24f0b8f CL |
918 | break; |
919 | case 0: | |
e24f0b8f CL |
920 | break; |
921 | default: | |
2d1db3b1 | 922 | /* Permanent failure */ |
2d1db3b1 | 923 | nr_failed++; |
e24f0b8f | 924 | break; |
2d1db3b1 | 925 | } |
b20a3503 CL |
926 | } |
927 | } | |
95a402c3 CL |
928 | rc = 0; |
929 | out: | |
b20a3503 CL |
930 | if (!swapwrite) |
931 | current->flags &= ~PF_SWAPWRITE; | |
932 | ||
aaa994b3 | 933 | putback_lru_pages(from); |
b20a3503 | 934 | |
95a402c3 CL |
935 | if (rc) |
936 | return rc; | |
b20a3503 | 937 | |
95a402c3 | 938 | return nr_failed + retry; |
b20a3503 | 939 | } |
95a402c3 | 940 | |
290408d4 NH |
941 | int migrate_huge_pages(struct list_head *from, |
942 | new_page_t get_new_page, unsigned long private, int offlining) | |
943 | { | |
944 | int retry = 1; | |
945 | int nr_failed = 0; | |
946 | int pass = 0; | |
947 | struct page *page; | |
948 | struct page *page2; | |
949 | int rc; | |
950 | ||
951 | for (pass = 0; pass < 10 && retry; pass++) { | |
952 | retry = 0; | |
953 | ||
954 | list_for_each_entry_safe(page, page2, from, lru) { | |
955 | cond_resched(); | |
956 | ||
957 | rc = unmap_and_move_huge_page(get_new_page, | |
958 | private, page, pass > 2, offlining); | |
959 | ||
960 | switch(rc) { | |
961 | case -ENOMEM: | |
962 | goto out; | |
963 | case -EAGAIN: | |
964 | retry++; | |
965 | break; | |
966 | case 0: | |
967 | break; | |
968 | default: | |
969 | /* Permanent failure */ | |
970 | nr_failed++; | |
971 | break; | |
972 | } | |
973 | } | |
974 | } | |
975 | rc = 0; | |
976 | out: | |
977 | ||
978 | list_for_each_entry_safe(page, page2, from, lru) | |
979 | put_page(page); | |
980 | ||
981 | if (rc) | |
982 | return rc; | |
983 | ||
984 | return nr_failed + retry; | |
985 | } | |
986 | ||
742755a1 CL |
987 | #ifdef CONFIG_NUMA |
988 | /* | |
989 | * Move a list of individual pages | |
990 | */ | |
991 | struct page_to_node { | |
992 | unsigned long addr; | |
993 | struct page *page; | |
994 | int node; | |
995 | int status; | |
996 | }; | |
997 | ||
998 | static struct page *new_page_node(struct page *p, unsigned long private, | |
999 | int **result) | |
1000 | { | |
1001 | struct page_to_node *pm = (struct page_to_node *)private; | |
1002 | ||
1003 | while (pm->node != MAX_NUMNODES && pm->page != p) | |
1004 | pm++; | |
1005 | ||
1006 | if (pm->node == MAX_NUMNODES) | |
1007 | return NULL; | |
1008 | ||
1009 | *result = &pm->status; | |
1010 | ||
6484eb3e | 1011 | return alloc_pages_exact_node(pm->node, |
769848c0 | 1012 | GFP_HIGHUSER_MOVABLE | GFP_THISNODE, 0); |
742755a1 CL |
1013 | } |
1014 | ||
1015 | /* | |
1016 | * Move a set of pages as indicated in the pm array. The addr | |
1017 | * field must be set to the virtual address of the page to be moved | |
1018 | * and the node number must contain a valid target node. | |
5e9a0f02 | 1019 | * The pm array ends with node = MAX_NUMNODES. |
742755a1 | 1020 | */ |
5e9a0f02 BG |
1021 | static int do_move_page_to_node_array(struct mm_struct *mm, |
1022 | struct page_to_node *pm, | |
1023 | int migrate_all) | |
742755a1 CL |
1024 | { |
1025 | int err; | |
1026 | struct page_to_node *pp; | |
1027 | LIST_HEAD(pagelist); | |
1028 | ||
1029 | down_read(&mm->mmap_sem); | |
1030 | ||
1031 | /* | |
1032 | * Build a list of pages to migrate | |
1033 | */ | |
742755a1 CL |
1034 | for (pp = pm; pp->node != MAX_NUMNODES; pp++) { |
1035 | struct vm_area_struct *vma; | |
1036 | struct page *page; | |
1037 | ||
742755a1 CL |
1038 | err = -EFAULT; |
1039 | vma = find_vma(mm, pp->addr); | |
0dc952dc | 1040 | if (!vma || !vma_migratable(vma)) |
742755a1 CL |
1041 | goto set_status; |
1042 | ||
1043 | page = follow_page(vma, pp->addr, FOLL_GET); | |
89f5b7da LT |
1044 | |
1045 | err = PTR_ERR(page); | |
1046 | if (IS_ERR(page)) | |
1047 | goto set_status; | |
1048 | ||
742755a1 CL |
1049 | err = -ENOENT; |
1050 | if (!page) | |
1051 | goto set_status; | |
1052 | ||
62b61f61 HD |
1053 | /* Use PageReserved to check for zero page */ |
1054 | if (PageReserved(page) || PageKsm(page)) | |
742755a1 CL |
1055 | goto put_and_set; |
1056 | ||
1057 | pp->page = page; | |
1058 | err = page_to_nid(page); | |
1059 | ||
1060 | if (err == pp->node) | |
1061 | /* | |
1062 | * Node already in the right place | |
1063 | */ | |
1064 | goto put_and_set; | |
1065 | ||
1066 | err = -EACCES; | |
1067 | if (page_mapcount(page) > 1 && | |
1068 | !migrate_all) | |
1069 | goto put_and_set; | |
1070 | ||
62695a84 | 1071 | err = isolate_lru_page(page); |
6d9c285a | 1072 | if (!err) { |
62695a84 | 1073 | list_add_tail(&page->lru, &pagelist); |
6d9c285a KM |
1074 | inc_zone_page_state(page, NR_ISOLATED_ANON + |
1075 | page_is_file_cache(page)); | |
1076 | } | |
742755a1 CL |
1077 | put_and_set: |
1078 | /* | |
1079 | * Either remove the duplicate refcount from | |
1080 | * isolate_lru_page() or drop the page ref if it was | |
1081 | * not isolated. | |
1082 | */ | |
1083 | put_page(page); | |
1084 | set_status: | |
1085 | pp->status = err; | |
1086 | } | |
1087 | ||
e78bbfa8 | 1088 | err = 0; |
742755a1 CL |
1089 | if (!list_empty(&pagelist)) |
1090 | err = migrate_pages(&pagelist, new_page_node, | |
62b61f61 | 1091 | (unsigned long)pm, 0); |
742755a1 CL |
1092 | |
1093 | up_read(&mm->mmap_sem); | |
1094 | return err; | |
1095 | } | |
1096 | ||
5e9a0f02 BG |
1097 | /* |
1098 | * Migrate an array of page address onto an array of nodes and fill | |
1099 | * the corresponding array of status. | |
1100 | */ | |
1101 | static int do_pages_move(struct mm_struct *mm, struct task_struct *task, | |
1102 | unsigned long nr_pages, | |
1103 | const void __user * __user *pages, | |
1104 | const int __user *nodes, | |
1105 | int __user *status, int flags) | |
1106 | { | |
3140a227 | 1107 | struct page_to_node *pm; |
5e9a0f02 | 1108 | nodemask_t task_nodes; |
3140a227 BG |
1109 | unsigned long chunk_nr_pages; |
1110 | unsigned long chunk_start; | |
1111 | int err; | |
5e9a0f02 BG |
1112 | |
1113 | task_nodes = cpuset_mems_allowed(task); | |
1114 | ||
3140a227 BG |
1115 | err = -ENOMEM; |
1116 | pm = (struct page_to_node *)__get_free_page(GFP_KERNEL); | |
1117 | if (!pm) | |
5e9a0f02 | 1118 | goto out; |
35282a2d BG |
1119 | |
1120 | migrate_prep(); | |
1121 | ||
5e9a0f02 | 1122 | /* |
3140a227 BG |
1123 | * Store a chunk of page_to_node array in a page, |
1124 | * but keep the last one as a marker | |
5e9a0f02 | 1125 | */ |
3140a227 | 1126 | chunk_nr_pages = (PAGE_SIZE / sizeof(struct page_to_node)) - 1; |
5e9a0f02 | 1127 | |
3140a227 BG |
1128 | for (chunk_start = 0; |
1129 | chunk_start < nr_pages; | |
1130 | chunk_start += chunk_nr_pages) { | |
1131 | int j; | |
5e9a0f02 | 1132 | |
3140a227 BG |
1133 | if (chunk_start + chunk_nr_pages > nr_pages) |
1134 | chunk_nr_pages = nr_pages - chunk_start; | |
1135 | ||
1136 | /* fill the chunk pm with addrs and nodes from user-space */ | |
1137 | for (j = 0; j < chunk_nr_pages; j++) { | |
1138 | const void __user *p; | |
5e9a0f02 BG |
1139 | int node; |
1140 | ||
3140a227 BG |
1141 | err = -EFAULT; |
1142 | if (get_user(p, pages + j + chunk_start)) | |
1143 | goto out_pm; | |
1144 | pm[j].addr = (unsigned long) p; | |
1145 | ||
1146 | if (get_user(node, nodes + j + chunk_start)) | |
5e9a0f02 BG |
1147 | goto out_pm; |
1148 | ||
1149 | err = -ENODEV; | |
6f5a55f1 LT |
1150 | if (node < 0 || node >= MAX_NUMNODES) |
1151 | goto out_pm; | |
1152 | ||
5e9a0f02 BG |
1153 | if (!node_state(node, N_HIGH_MEMORY)) |
1154 | goto out_pm; | |
1155 | ||
1156 | err = -EACCES; | |
1157 | if (!node_isset(node, task_nodes)) | |
1158 | goto out_pm; | |
1159 | ||
3140a227 BG |
1160 | pm[j].node = node; |
1161 | } | |
1162 | ||
1163 | /* End marker for this chunk */ | |
1164 | pm[chunk_nr_pages].node = MAX_NUMNODES; | |
1165 | ||
1166 | /* Migrate this chunk */ | |
1167 | err = do_move_page_to_node_array(mm, pm, | |
1168 | flags & MPOL_MF_MOVE_ALL); | |
1169 | if (err < 0) | |
1170 | goto out_pm; | |
5e9a0f02 | 1171 | |
5e9a0f02 | 1172 | /* Return status information */ |
3140a227 BG |
1173 | for (j = 0; j < chunk_nr_pages; j++) |
1174 | if (put_user(pm[j].status, status + j + chunk_start)) { | |
5e9a0f02 | 1175 | err = -EFAULT; |
3140a227 BG |
1176 | goto out_pm; |
1177 | } | |
1178 | } | |
1179 | err = 0; | |
5e9a0f02 BG |
1180 | |
1181 | out_pm: | |
3140a227 | 1182 | free_page((unsigned long)pm); |
5e9a0f02 BG |
1183 | out: |
1184 | return err; | |
1185 | } | |
1186 | ||
742755a1 | 1187 | /* |
2f007e74 | 1188 | * Determine the nodes of an array of pages and store it in an array of status. |
742755a1 | 1189 | */ |
80bba129 BG |
1190 | static void do_pages_stat_array(struct mm_struct *mm, unsigned long nr_pages, |
1191 | const void __user **pages, int *status) | |
742755a1 | 1192 | { |
2f007e74 | 1193 | unsigned long i; |
2f007e74 | 1194 | |
742755a1 CL |
1195 | down_read(&mm->mmap_sem); |
1196 | ||
2f007e74 | 1197 | for (i = 0; i < nr_pages; i++) { |
80bba129 | 1198 | unsigned long addr = (unsigned long)(*pages); |
742755a1 CL |
1199 | struct vm_area_struct *vma; |
1200 | struct page *page; | |
c095adbc | 1201 | int err = -EFAULT; |
2f007e74 BG |
1202 | |
1203 | vma = find_vma(mm, addr); | |
742755a1 CL |
1204 | if (!vma) |
1205 | goto set_status; | |
1206 | ||
2f007e74 | 1207 | page = follow_page(vma, addr, 0); |
89f5b7da LT |
1208 | |
1209 | err = PTR_ERR(page); | |
1210 | if (IS_ERR(page)) | |
1211 | goto set_status; | |
1212 | ||
742755a1 CL |
1213 | err = -ENOENT; |
1214 | /* Use PageReserved to check for zero page */ | |
62b61f61 | 1215 | if (!page || PageReserved(page) || PageKsm(page)) |
742755a1 CL |
1216 | goto set_status; |
1217 | ||
1218 | err = page_to_nid(page); | |
1219 | set_status: | |
80bba129 BG |
1220 | *status = err; |
1221 | ||
1222 | pages++; | |
1223 | status++; | |
1224 | } | |
1225 | ||
1226 | up_read(&mm->mmap_sem); | |
1227 | } | |
1228 | ||
1229 | /* | |
1230 | * Determine the nodes of a user array of pages and store it in | |
1231 | * a user array of status. | |
1232 | */ | |
1233 | static int do_pages_stat(struct mm_struct *mm, unsigned long nr_pages, | |
1234 | const void __user * __user *pages, | |
1235 | int __user *status) | |
1236 | { | |
1237 | #define DO_PAGES_STAT_CHUNK_NR 16 | |
1238 | const void __user *chunk_pages[DO_PAGES_STAT_CHUNK_NR]; | |
1239 | int chunk_status[DO_PAGES_STAT_CHUNK_NR]; | |
80bba129 | 1240 | |
87b8d1ad PA |
1241 | while (nr_pages) { |
1242 | unsigned long chunk_nr; | |
80bba129 | 1243 | |
87b8d1ad PA |
1244 | chunk_nr = nr_pages; |
1245 | if (chunk_nr > DO_PAGES_STAT_CHUNK_NR) | |
1246 | chunk_nr = DO_PAGES_STAT_CHUNK_NR; | |
1247 | ||
1248 | if (copy_from_user(chunk_pages, pages, chunk_nr * sizeof(*chunk_pages))) | |
1249 | break; | |
80bba129 BG |
1250 | |
1251 | do_pages_stat_array(mm, chunk_nr, chunk_pages, chunk_status); | |
1252 | ||
87b8d1ad PA |
1253 | if (copy_to_user(status, chunk_status, chunk_nr * sizeof(*status))) |
1254 | break; | |
742755a1 | 1255 | |
87b8d1ad PA |
1256 | pages += chunk_nr; |
1257 | status += chunk_nr; | |
1258 | nr_pages -= chunk_nr; | |
1259 | } | |
1260 | return nr_pages ? -EFAULT : 0; | |
742755a1 CL |
1261 | } |
1262 | ||
1263 | /* | |
1264 | * Move a list of pages in the address space of the currently executing | |
1265 | * process. | |
1266 | */ | |
938bb9f5 HC |
1267 | SYSCALL_DEFINE6(move_pages, pid_t, pid, unsigned long, nr_pages, |
1268 | const void __user * __user *, pages, | |
1269 | const int __user *, nodes, | |
1270 | int __user *, status, int, flags) | |
742755a1 | 1271 | { |
c69e8d9c | 1272 | const struct cred *cred = current_cred(), *tcred; |
742755a1 | 1273 | struct task_struct *task; |
742755a1 | 1274 | struct mm_struct *mm; |
5e9a0f02 | 1275 | int err; |
742755a1 CL |
1276 | |
1277 | /* Check flags */ | |
1278 | if (flags & ~(MPOL_MF_MOVE|MPOL_MF_MOVE_ALL)) | |
1279 | return -EINVAL; | |
1280 | ||
1281 | if ((flags & MPOL_MF_MOVE_ALL) && !capable(CAP_SYS_NICE)) | |
1282 | return -EPERM; | |
1283 | ||
1284 | /* Find the mm_struct */ | |
1285 | read_lock(&tasklist_lock); | |
228ebcbe | 1286 | task = pid ? find_task_by_vpid(pid) : current; |
742755a1 CL |
1287 | if (!task) { |
1288 | read_unlock(&tasklist_lock); | |
1289 | return -ESRCH; | |
1290 | } | |
1291 | mm = get_task_mm(task); | |
1292 | read_unlock(&tasklist_lock); | |
1293 | ||
1294 | if (!mm) | |
1295 | return -EINVAL; | |
1296 | ||
1297 | /* | |
1298 | * Check if this process has the right to modify the specified | |
1299 | * process. The right exists if the process has administrative | |
1300 | * capabilities, superuser privileges or the same | |
1301 | * userid as the target process. | |
1302 | */ | |
c69e8d9c DH |
1303 | rcu_read_lock(); |
1304 | tcred = __task_cred(task); | |
b6dff3ec DH |
1305 | if (cred->euid != tcred->suid && cred->euid != tcred->uid && |
1306 | cred->uid != tcred->suid && cred->uid != tcred->uid && | |
742755a1 | 1307 | !capable(CAP_SYS_NICE)) { |
c69e8d9c | 1308 | rcu_read_unlock(); |
742755a1 | 1309 | err = -EPERM; |
5e9a0f02 | 1310 | goto out; |
742755a1 | 1311 | } |
c69e8d9c | 1312 | rcu_read_unlock(); |
742755a1 | 1313 | |
86c3a764 DQ |
1314 | err = security_task_movememory(task); |
1315 | if (err) | |
5e9a0f02 | 1316 | goto out; |
86c3a764 | 1317 | |
5e9a0f02 BG |
1318 | if (nodes) { |
1319 | err = do_pages_move(mm, task, nr_pages, pages, nodes, status, | |
1320 | flags); | |
1321 | } else { | |
2f007e74 | 1322 | err = do_pages_stat(mm, nr_pages, pages, status); |
742755a1 CL |
1323 | } |
1324 | ||
742755a1 | 1325 | out: |
742755a1 CL |
1326 | mmput(mm); |
1327 | return err; | |
1328 | } | |
742755a1 | 1329 | |
7b2259b3 CL |
1330 | /* |
1331 | * Call migration functions in the vma_ops that may prepare | |
1332 | * memory in a vm for migration. migration functions may perform | |
1333 | * the migration for vmas that do not have an underlying page struct. | |
1334 | */ | |
1335 | int migrate_vmas(struct mm_struct *mm, const nodemask_t *to, | |
1336 | const nodemask_t *from, unsigned long flags) | |
1337 | { | |
1338 | struct vm_area_struct *vma; | |
1339 | int err = 0; | |
1340 | ||
1001c9fb | 1341 | for (vma = mm->mmap; vma && !err; vma = vma->vm_next) { |
7b2259b3 CL |
1342 | if (vma->vm_ops && vma->vm_ops->migrate) { |
1343 | err = vma->vm_ops->migrate(vma, to, from, flags); | |
1344 | if (err) | |
1345 | break; | |
1346 | } | |
1347 | } | |
1348 | return err; | |
1349 | } | |
83d1674a | 1350 | #endif |