Commit | Line | Data |
---|---|---|
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> |
5a0e3ad6 | 35 | #include <linux/gfp.h> |
b20a3503 CL |
36 | |
37 | #include "internal.h" | |
38 | ||
b20a3503 CL |
39 | #define lru_to_page(_head) (list_entry((_head)->prev, struct page, lru)) |
40 | ||
b20a3503 | 41 | /* |
742755a1 | 42 | * migrate_prep() needs to be called before we start compiling a list of pages |
748446bb MG |
43 | * to be migrated using isolate_lru_page(). If scheduling work on other CPUs is |
44 | * undesirable, use migrate_prep_local() | |
b20a3503 CL |
45 | */ |
46 | int migrate_prep(void) | |
47 | { | |
b20a3503 CL |
48 | /* |
49 | * Clear the LRU lists so pages can be isolated. | |
50 | * Note that pages may be moved off the LRU after we have | |
51 | * drained them. Those pages will fail to migrate like other | |
52 | * pages that may be busy. | |
53 | */ | |
54 | lru_add_drain_all(); | |
55 | ||
56 | return 0; | |
57 | } | |
58 | ||
748446bb MG |
59 | /* Do the necessary work of migrate_prep but not if it involves other CPUs */ |
60 | int migrate_prep_local(void) | |
61 | { | |
62 | lru_add_drain(); | |
63 | ||
64 | return 0; | |
65 | } | |
66 | ||
b20a3503 | 67 | /* |
894bc310 LS |
68 | * Add isolated pages on the list back to the LRU under page lock |
69 | * to avoid leaking evictable pages back onto unevictable list. | |
b20a3503 | 70 | */ |
e13861d8 | 71 | void putback_lru_pages(struct list_head *l) |
b20a3503 CL |
72 | { |
73 | struct page *page; | |
74 | struct page *page2; | |
b20a3503 CL |
75 | |
76 | list_for_each_entry_safe(page, page2, l, lru) { | |
e24f0b8f | 77 | list_del(&page->lru); |
a731286d | 78 | dec_zone_page_state(page, NR_ISOLATED_ANON + |
6c0b1351 | 79 | page_is_file_cache(page)); |
894bc310 | 80 | putback_lru_page(page); |
b20a3503 | 81 | } |
b20a3503 CL |
82 | } |
83 | ||
0697212a CL |
84 | /* |
85 | * Restore a potential migration pte to a working pte entry | |
86 | */ | |
e9995ef9 HD |
87 | static int remove_migration_pte(struct page *new, struct vm_area_struct *vma, |
88 | unsigned long addr, void *old) | |
0697212a CL |
89 | { |
90 | struct mm_struct *mm = vma->vm_mm; | |
91 | swp_entry_t entry; | |
92 | pgd_t *pgd; | |
93 | pud_t *pud; | |
94 | pmd_t *pmd; | |
95 | pte_t *ptep, pte; | |
96 | spinlock_t *ptl; | |
97 | ||
98 | pgd = pgd_offset(mm, addr); | |
99 | if (!pgd_present(*pgd)) | |
e9995ef9 | 100 | goto out; |
0697212a CL |
101 | |
102 | pud = pud_offset(pgd, addr); | |
103 | if (!pud_present(*pud)) | |
e9995ef9 | 104 | goto out; |
0697212a CL |
105 | |
106 | pmd = pmd_offset(pud, addr); | |
107 | if (!pmd_present(*pmd)) | |
e9995ef9 | 108 | goto out; |
0697212a CL |
109 | |
110 | ptep = pte_offset_map(pmd, addr); | |
111 | ||
112 | if (!is_swap_pte(*ptep)) { | |
113 | pte_unmap(ptep); | |
e9995ef9 | 114 | goto out; |
0697212a CL |
115 | } |
116 | ||
117 | ptl = pte_lockptr(mm, pmd); | |
118 | spin_lock(ptl); | |
119 | pte = *ptep; | |
120 | if (!is_swap_pte(pte)) | |
e9995ef9 | 121 | goto unlock; |
0697212a CL |
122 | |
123 | entry = pte_to_swp_entry(pte); | |
124 | ||
e9995ef9 HD |
125 | if (!is_migration_entry(entry) || |
126 | migration_entry_to_page(entry) != old) | |
127 | goto unlock; | |
0697212a | 128 | |
0697212a CL |
129 | get_page(new); |
130 | pte = pte_mkold(mk_pte(new, vma->vm_page_prot)); | |
131 | if (is_write_migration_entry(entry)) | |
132 | pte = pte_mkwrite(pte); | |
97ee0524 | 133 | flush_cache_page(vma, addr, pte_pfn(pte)); |
0697212a | 134 | set_pte_at(mm, addr, ptep, pte); |
04e62a29 CL |
135 | |
136 | if (PageAnon(new)) | |
137 | page_add_anon_rmap(new, vma, addr); | |
138 | else | |
139 | page_add_file_rmap(new); | |
140 | ||
141 | /* No need to invalidate - it was non-present before */ | |
4b3073e1 | 142 | update_mmu_cache(vma, addr, ptep); |
e9995ef9 | 143 | unlock: |
0697212a | 144 | pte_unmap_unlock(ptep, ptl); |
e9995ef9 HD |
145 | out: |
146 | return SWAP_AGAIN; | |
0697212a CL |
147 | } |
148 | ||
04e62a29 CL |
149 | /* |
150 | * Get rid of all migration entries and replace them by | |
151 | * references to the indicated page. | |
152 | */ | |
153 | static void remove_migration_ptes(struct page *old, struct page *new) | |
154 | { | |
e9995ef9 | 155 | rmap_walk(new, remove_migration_pte, old); |
04e62a29 CL |
156 | } |
157 | ||
0697212a CL |
158 | /* |
159 | * Something used the pte of a page under migration. We need to | |
160 | * get to the page and wait until migration is finished. | |
161 | * When we return from this function the fault will be retried. | |
162 | * | |
163 | * This function is called from do_swap_page(). | |
164 | */ | |
165 | void migration_entry_wait(struct mm_struct *mm, pmd_t *pmd, | |
166 | unsigned long address) | |
167 | { | |
168 | pte_t *ptep, pte; | |
169 | spinlock_t *ptl; | |
170 | swp_entry_t entry; | |
171 | struct page *page; | |
172 | ||
173 | ptep = pte_offset_map_lock(mm, pmd, address, &ptl); | |
174 | pte = *ptep; | |
175 | if (!is_swap_pte(pte)) | |
176 | goto out; | |
177 | ||
178 | entry = pte_to_swp_entry(pte); | |
179 | if (!is_migration_entry(entry)) | |
180 | goto out; | |
181 | ||
182 | page = migration_entry_to_page(entry); | |
183 | ||
e286781d NP |
184 | /* |
185 | * Once radix-tree replacement of page migration started, page_count | |
186 | * *must* be zero. And, we don't want to call wait_on_page_locked() | |
187 | * against a page without get_page(). | |
188 | * So, we use get_page_unless_zero(), here. Even failed, page fault | |
189 | * will occur again. | |
190 | */ | |
191 | if (!get_page_unless_zero(page)) | |
192 | goto out; | |
0697212a CL |
193 | pte_unmap_unlock(ptep, ptl); |
194 | wait_on_page_locked(page); | |
195 | put_page(page); | |
196 | return; | |
197 | out: | |
198 | pte_unmap_unlock(ptep, ptl); | |
199 | } | |
200 | ||
b20a3503 | 201 | /* |
c3fcf8a5 | 202 | * Replace the page in the mapping. |
5b5c7120 CL |
203 | * |
204 | * The number of remaining references must be: | |
205 | * 1 for anonymous pages without a mapping | |
206 | * 2 for pages with a mapping | |
266cf658 | 207 | * 3 for pages with a mapping and PagePrivate/PagePrivate2 set. |
b20a3503 | 208 | */ |
2d1db3b1 CL |
209 | static int migrate_page_move_mapping(struct address_space *mapping, |
210 | struct page *newpage, struct page *page) | |
b20a3503 | 211 | { |
e286781d | 212 | int expected_count; |
7cf9c2c7 | 213 | void **pslot; |
b20a3503 | 214 | |
6c5240ae | 215 | if (!mapping) { |
0e8c7d0f | 216 | /* Anonymous page without mapping */ |
6c5240ae CL |
217 | if (page_count(page) != 1) |
218 | return -EAGAIN; | |
219 | return 0; | |
220 | } | |
221 | ||
19fd6231 | 222 | spin_lock_irq(&mapping->tree_lock); |
b20a3503 | 223 | |
7cf9c2c7 NP |
224 | pslot = radix_tree_lookup_slot(&mapping->page_tree, |
225 | page_index(page)); | |
b20a3503 | 226 | |
edcf4748 | 227 | expected_count = 2 + page_has_private(page); |
e286781d | 228 | if (page_count(page) != expected_count || |
7cf9c2c7 | 229 | (struct page *)radix_tree_deref_slot(pslot) != page) { |
19fd6231 | 230 | spin_unlock_irq(&mapping->tree_lock); |
e23ca00b | 231 | return -EAGAIN; |
b20a3503 CL |
232 | } |
233 | ||
e286781d | 234 | if (!page_freeze_refs(page, expected_count)) { |
19fd6231 | 235 | spin_unlock_irq(&mapping->tree_lock); |
e286781d NP |
236 | return -EAGAIN; |
237 | } | |
238 | ||
b20a3503 CL |
239 | /* |
240 | * Now we know that no one else is looking at the page. | |
b20a3503 | 241 | */ |
7cf9c2c7 | 242 | get_page(newpage); /* add cache reference */ |
b20a3503 CL |
243 | if (PageSwapCache(page)) { |
244 | SetPageSwapCache(newpage); | |
245 | set_page_private(newpage, page_private(page)); | |
246 | } | |
247 | ||
7cf9c2c7 NP |
248 | radix_tree_replace_slot(pslot, newpage); |
249 | ||
e286781d | 250 | page_unfreeze_refs(page, expected_count); |
7cf9c2c7 NP |
251 | /* |
252 | * Drop cache reference from old page. | |
253 | * We know this isn't the last reference. | |
254 | */ | |
b20a3503 | 255 | __put_page(page); |
7cf9c2c7 | 256 | |
0e8c7d0f CL |
257 | /* |
258 | * If moved to a different zone then also account | |
259 | * the page for that zone. Other VM counters will be | |
260 | * taken care of when we establish references to the | |
261 | * new page and drop references to the old page. | |
262 | * | |
263 | * Note that anonymous pages are accounted for | |
264 | * via NR_FILE_PAGES and NR_ANON_PAGES if they | |
265 | * are mapped to swap space. | |
266 | */ | |
267 | __dec_zone_page_state(page, NR_FILE_PAGES); | |
268 | __inc_zone_page_state(newpage, NR_FILE_PAGES); | |
4b02108a KM |
269 | if (PageSwapBacked(page)) { |
270 | __dec_zone_page_state(page, NR_SHMEM); | |
271 | __inc_zone_page_state(newpage, NR_SHMEM); | |
272 | } | |
19fd6231 | 273 | spin_unlock_irq(&mapping->tree_lock); |
b20a3503 CL |
274 | |
275 | return 0; | |
276 | } | |
b20a3503 CL |
277 | |
278 | /* | |
279 | * Copy the page to its new location | |
280 | */ | |
e7340f73 | 281 | static void migrate_page_copy(struct page *newpage, struct page *page) |
b20a3503 CL |
282 | { |
283 | copy_highpage(newpage, page); | |
284 | ||
285 | if (PageError(page)) | |
286 | SetPageError(newpage); | |
287 | if (PageReferenced(page)) | |
288 | SetPageReferenced(newpage); | |
289 | if (PageUptodate(page)) | |
290 | SetPageUptodate(newpage); | |
894bc310 LS |
291 | if (TestClearPageActive(page)) { |
292 | VM_BUG_ON(PageUnevictable(page)); | |
b20a3503 | 293 | SetPageActive(newpage); |
418b27ef LS |
294 | } else if (TestClearPageUnevictable(page)) |
295 | SetPageUnevictable(newpage); | |
b20a3503 CL |
296 | if (PageChecked(page)) |
297 | SetPageChecked(newpage); | |
298 | if (PageMappedToDisk(page)) | |
299 | SetPageMappedToDisk(newpage); | |
300 | ||
301 | if (PageDirty(page)) { | |
302 | clear_page_dirty_for_io(page); | |
3a902c5f NP |
303 | /* |
304 | * Want to mark the page and the radix tree as dirty, and | |
305 | * redo the accounting that clear_page_dirty_for_io undid, | |
306 | * but we can't use set_page_dirty because that function | |
307 | * is actually a signal that all of the page has become dirty. | |
308 | * Wheras only part of our page may be dirty. | |
309 | */ | |
310 | __set_page_dirty_nobuffers(newpage); | |
b20a3503 CL |
311 | } |
312 | ||
b291f000 | 313 | mlock_migrate_page(newpage, page); |
e9995ef9 | 314 | ksm_migrate_page(newpage, page); |
b291f000 | 315 | |
b20a3503 | 316 | ClearPageSwapCache(page); |
b20a3503 CL |
317 | ClearPagePrivate(page); |
318 | set_page_private(page, 0); | |
319 | page->mapping = NULL; | |
320 | ||
321 | /* | |
322 | * If any waiters have accumulated on the new page then | |
323 | * wake them up. | |
324 | */ | |
325 | if (PageWriteback(newpage)) | |
326 | end_page_writeback(newpage); | |
327 | } | |
b20a3503 | 328 | |
1d8b85cc CL |
329 | /************************************************************ |
330 | * Migration functions | |
331 | ***********************************************************/ | |
332 | ||
333 | /* Always fail migration. Used for mappings that are not movable */ | |
2d1db3b1 CL |
334 | int fail_migrate_page(struct address_space *mapping, |
335 | struct page *newpage, struct page *page) | |
1d8b85cc CL |
336 | { |
337 | return -EIO; | |
338 | } | |
339 | EXPORT_SYMBOL(fail_migrate_page); | |
340 | ||
b20a3503 CL |
341 | /* |
342 | * Common logic to directly migrate a single page suitable for | |
266cf658 | 343 | * pages that do not use PagePrivate/PagePrivate2. |
b20a3503 CL |
344 | * |
345 | * Pages are locked upon entry and exit. | |
346 | */ | |
2d1db3b1 CL |
347 | int migrate_page(struct address_space *mapping, |
348 | struct page *newpage, struct page *page) | |
b20a3503 CL |
349 | { |
350 | int rc; | |
351 | ||
352 | BUG_ON(PageWriteback(page)); /* Writeback must be complete */ | |
353 | ||
2d1db3b1 | 354 | rc = migrate_page_move_mapping(mapping, newpage, page); |
b20a3503 CL |
355 | |
356 | if (rc) | |
357 | return rc; | |
358 | ||
359 | migrate_page_copy(newpage, page); | |
b20a3503 CL |
360 | return 0; |
361 | } | |
362 | EXPORT_SYMBOL(migrate_page); | |
363 | ||
9361401e | 364 | #ifdef CONFIG_BLOCK |
1d8b85cc CL |
365 | /* |
366 | * Migration function for pages with buffers. This function can only be used | |
367 | * if the underlying filesystem guarantees that no other references to "page" | |
368 | * exist. | |
369 | */ | |
2d1db3b1 CL |
370 | int buffer_migrate_page(struct address_space *mapping, |
371 | struct page *newpage, struct page *page) | |
1d8b85cc | 372 | { |
1d8b85cc CL |
373 | struct buffer_head *bh, *head; |
374 | int rc; | |
375 | ||
1d8b85cc | 376 | if (!page_has_buffers(page)) |
2d1db3b1 | 377 | return migrate_page(mapping, newpage, page); |
1d8b85cc CL |
378 | |
379 | head = page_buffers(page); | |
380 | ||
2d1db3b1 | 381 | rc = migrate_page_move_mapping(mapping, newpage, page); |
1d8b85cc CL |
382 | |
383 | if (rc) | |
384 | return rc; | |
385 | ||
386 | bh = head; | |
387 | do { | |
388 | get_bh(bh); | |
389 | lock_buffer(bh); | |
390 | bh = bh->b_this_page; | |
391 | ||
392 | } while (bh != head); | |
393 | ||
394 | ClearPagePrivate(page); | |
395 | set_page_private(newpage, page_private(page)); | |
396 | set_page_private(page, 0); | |
397 | put_page(page); | |
398 | get_page(newpage); | |
399 | ||
400 | bh = head; | |
401 | do { | |
402 | set_bh_page(bh, newpage, bh_offset(bh)); | |
403 | bh = bh->b_this_page; | |
404 | ||
405 | } while (bh != head); | |
406 | ||
407 | SetPagePrivate(newpage); | |
408 | ||
409 | migrate_page_copy(newpage, page); | |
410 | ||
411 | bh = head; | |
412 | do { | |
413 | unlock_buffer(bh); | |
414 | put_bh(bh); | |
415 | bh = bh->b_this_page; | |
416 | ||
417 | } while (bh != head); | |
418 | ||
419 | return 0; | |
420 | } | |
421 | EXPORT_SYMBOL(buffer_migrate_page); | |
9361401e | 422 | #endif |
1d8b85cc | 423 | |
04e62a29 CL |
424 | /* |
425 | * Writeback a page to clean the dirty state | |
426 | */ | |
427 | static int writeout(struct address_space *mapping, struct page *page) | |
8351a6e4 | 428 | { |
04e62a29 CL |
429 | struct writeback_control wbc = { |
430 | .sync_mode = WB_SYNC_NONE, | |
431 | .nr_to_write = 1, | |
432 | .range_start = 0, | |
433 | .range_end = LLONG_MAX, | |
434 | .nonblocking = 1, | |
435 | .for_reclaim = 1 | |
436 | }; | |
437 | int rc; | |
438 | ||
439 | if (!mapping->a_ops->writepage) | |
440 | /* No write method for the address space */ | |
441 | return -EINVAL; | |
442 | ||
443 | if (!clear_page_dirty_for_io(page)) | |
444 | /* Someone else already triggered a write */ | |
445 | return -EAGAIN; | |
446 | ||
8351a6e4 | 447 | /* |
04e62a29 CL |
448 | * A dirty page may imply that the underlying filesystem has |
449 | * the page on some queue. So the page must be clean for | |
450 | * migration. Writeout may mean we loose the lock and the | |
451 | * page state is no longer what we checked for earlier. | |
452 | * At this point we know that the migration attempt cannot | |
453 | * be successful. | |
8351a6e4 | 454 | */ |
04e62a29 | 455 | remove_migration_ptes(page, page); |
8351a6e4 | 456 | |
04e62a29 | 457 | rc = mapping->a_ops->writepage(page, &wbc); |
8351a6e4 | 458 | |
04e62a29 CL |
459 | if (rc != AOP_WRITEPAGE_ACTIVATE) |
460 | /* unlocked. Relock */ | |
461 | lock_page(page); | |
462 | ||
bda8550d | 463 | return (rc < 0) ? -EIO : -EAGAIN; |
04e62a29 CL |
464 | } |
465 | ||
466 | /* | |
467 | * Default handling if a filesystem does not provide a migration function. | |
468 | */ | |
469 | static int fallback_migrate_page(struct address_space *mapping, | |
470 | struct page *newpage, struct page *page) | |
471 | { | |
472 | if (PageDirty(page)) | |
473 | return writeout(mapping, page); | |
8351a6e4 CL |
474 | |
475 | /* | |
476 | * Buffers may be managed in a filesystem specific way. | |
477 | * We must have no buffers or drop them. | |
478 | */ | |
266cf658 | 479 | if (page_has_private(page) && |
8351a6e4 CL |
480 | !try_to_release_page(page, GFP_KERNEL)) |
481 | return -EAGAIN; | |
482 | ||
483 | return migrate_page(mapping, newpage, page); | |
484 | } | |
485 | ||
e24f0b8f CL |
486 | /* |
487 | * Move a page to a newly allocated page | |
488 | * The page is locked and all ptes have been successfully removed. | |
489 | * | |
490 | * The new page will have replaced the old page if this function | |
491 | * is successful. | |
894bc310 LS |
492 | * |
493 | * Return value: | |
494 | * < 0 - error code | |
495 | * == 0 - success | |
e24f0b8f | 496 | */ |
3fe2011f MG |
497 | static int move_to_new_page(struct page *newpage, struct page *page, |
498 | int remap_swapcache) | |
e24f0b8f CL |
499 | { |
500 | struct address_space *mapping; | |
501 | int rc; | |
502 | ||
503 | /* | |
504 | * Block others from accessing the page when we get around to | |
505 | * establishing additional references. We are the only one | |
506 | * holding a reference to the new page at this point. | |
507 | */ | |
529ae9aa | 508 | if (!trylock_page(newpage)) |
e24f0b8f CL |
509 | BUG(); |
510 | ||
511 | /* Prepare mapping for the new page.*/ | |
512 | newpage->index = page->index; | |
513 | newpage->mapping = page->mapping; | |
b2e18538 RR |
514 | if (PageSwapBacked(page)) |
515 | SetPageSwapBacked(newpage); | |
e24f0b8f CL |
516 | |
517 | mapping = page_mapping(page); | |
518 | if (!mapping) | |
519 | rc = migrate_page(mapping, newpage, page); | |
520 | else if (mapping->a_ops->migratepage) | |
521 | /* | |
522 | * Most pages have a mapping and most filesystems | |
523 | * should provide a migration function. Anonymous | |
524 | * pages are part of swap space which also has its | |
525 | * own migration function. This is the most common | |
526 | * path for page migration. | |
527 | */ | |
528 | rc = mapping->a_ops->migratepage(mapping, | |
529 | newpage, page); | |
530 | else | |
531 | rc = fallback_migrate_page(mapping, newpage, page); | |
532 | ||
3fe2011f | 533 | if (rc) { |
e24f0b8f | 534 | newpage->mapping = NULL; |
3fe2011f MG |
535 | } else { |
536 | if (remap_swapcache) | |
537 | remove_migration_ptes(page, newpage); | |
538 | } | |
e24f0b8f CL |
539 | |
540 | unlock_page(newpage); | |
541 | ||
542 | return rc; | |
543 | } | |
544 | ||
545 | /* | |
546 | * Obtain the lock on page, remove all ptes and migrate the page | |
547 | * to the newly allocated page in newpage. | |
548 | */ | |
95a402c3 | 549 | static int unmap_and_move(new_page_t get_new_page, unsigned long private, |
62b61f61 | 550 | struct page *page, int force, int offlining) |
e24f0b8f CL |
551 | { |
552 | int rc = 0; | |
742755a1 CL |
553 | int *result = NULL; |
554 | struct page *newpage = get_new_page(page, private, &result); | |
3fe2011f | 555 | int remap_swapcache = 1; |
989f89c5 | 556 | int rcu_locked = 0; |
ae41be37 | 557 | int charge = 0; |
e00e4316 | 558 | struct mem_cgroup *mem = NULL; |
3f6c8272 | 559 | struct anon_vma *anon_vma = NULL; |
95a402c3 CL |
560 | |
561 | if (!newpage) | |
562 | return -ENOMEM; | |
e24f0b8f | 563 | |
894bc310 | 564 | if (page_count(page) == 1) { |
e24f0b8f | 565 | /* page was freed from under us. So we are done. */ |
95a402c3 | 566 | goto move_newpage; |
894bc310 | 567 | } |
e24f0b8f | 568 | |
e8589cc1 | 569 | /* prepare cgroup just returns 0 or -ENOMEM */ |
e24f0b8f | 570 | rc = -EAGAIN; |
01b1ae63 | 571 | |
529ae9aa | 572 | if (!trylock_page(page)) { |
e24f0b8f | 573 | if (!force) |
95a402c3 | 574 | goto move_newpage; |
e24f0b8f CL |
575 | lock_page(page); |
576 | } | |
577 | ||
62b61f61 HD |
578 | /* |
579 | * Only memory hotplug's offline_pages() caller has locked out KSM, | |
580 | * and can safely migrate a KSM page. The other cases have skipped | |
581 | * PageKsm along with PageReserved - but it is only now when we have | |
582 | * the page lock that we can be certain it will not go KSM beneath us | |
583 | * (KSM will not upgrade a page from PageAnon to PageKsm when it sees | |
584 | * its pagecount raised, but only here do we take the page lock which | |
585 | * serializes that). | |
586 | */ | |
587 | if (PageKsm(page) && !offlining) { | |
588 | rc = -EBUSY; | |
589 | goto unlock; | |
590 | } | |
591 | ||
01b1ae63 | 592 | /* charge against new page */ |
ac39cf8c | 593 | charge = mem_cgroup_prepare_migration(page, newpage, &mem); |
01b1ae63 KH |
594 | if (charge == -ENOMEM) { |
595 | rc = -ENOMEM; | |
596 | goto unlock; | |
597 | } | |
598 | BUG_ON(charge); | |
599 | ||
e24f0b8f CL |
600 | if (PageWriteback(page)) { |
601 | if (!force) | |
01b1ae63 | 602 | goto uncharge; |
e24f0b8f CL |
603 | wait_on_page_writeback(page); |
604 | } | |
e24f0b8f | 605 | /* |
dc386d4d KH |
606 | * By try_to_unmap(), page->mapcount goes down to 0 here. In this case, |
607 | * we cannot notice that anon_vma is freed while we migrates a page. | |
608 | * This rcu_read_lock() delays freeing anon_vma pointer until the end | |
609 | * of migration. File cache pages are no problem because of page_lock() | |
989f89c5 KH |
610 | * File Caches may use write_page() or lock_page() in migration, then, |
611 | * just care Anon page here. | |
dc386d4d | 612 | */ |
989f89c5 KH |
613 | if (PageAnon(page)) { |
614 | rcu_read_lock(); | |
615 | rcu_locked = 1; | |
67b9509b | 616 | |
3fe2011f MG |
617 | /* Determine how to safely use anon_vma */ |
618 | if (!page_mapped(page)) { | |
619 | if (!PageSwapCache(page)) | |
620 | goto rcu_unlock; | |
67b9509b | 621 | |
3fe2011f MG |
622 | /* |
623 | * We cannot be sure that the anon_vma of an unmapped | |
624 | * swapcache page is safe to use because we don't | |
625 | * know in advance if the VMA that this page belonged | |
626 | * to still exists. If the VMA and others sharing the | |
627 | * data have been freed, then the anon_vma could | |
628 | * already be invalid. | |
629 | * | |
630 | * To avoid this possibility, swapcache pages get | |
631 | * migrated but are not remapped when migration | |
632 | * completes | |
633 | */ | |
634 | remap_swapcache = 0; | |
635 | } else { | |
636 | /* | |
637 | * Take a reference count on the anon_vma if the | |
638 | * page is mapped so that it is guaranteed to | |
639 | * exist when the page is remapped later | |
640 | */ | |
641 | anon_vma = page_anon_vma(page); | |
642 | atomic_inc(&anon_vma->external_refcount); | |
643 | } | |
989f89c5 | 644 | } |
62e1c553 | 645 | |
dc386d4d | 646 | /* |
62e1c553 SL |
647 | * Corner case handling: |
648 | * 1. When a new swap-cache page is read into, it is added to the LRU | |
649 | * and treated as swapcache but it has no rmap yet. | |
650 | * Calling try_to_unmap() against a page->mapping==NULL page will | |
651 | * trigger a BUG. So handle it here. | |
652 | * 2. An orphaned page (see truncate_complete_page) might have | |
653 | * fs-private metadata. The page can be picked up due to memory | |
654 | * offlining. Everywhere else except page reclaim, the page is | |
655 | * invisible to the vm, so the page can not be migrated. So try to | |
656 | * free the metadata, so the page can be freed. | |
e24f0b8f | 657 | */ |
62e1c553 | 658 | if (!page->mapping) { |
266cf658 | 659 | if (!PageAnon(page) && page_has_private(page)) { |
62e1c553 SL |
660 | /* |
661 | * Go direct to try_to_free_buffers() here because | |
662 | * a) that's what try_to_release_page() would do anyway | |
663 | * b) we may be under rcu_read_lock() here, so we can't | |
664 | * use GFP_KERNEL which is what try_to_release_page() | |
665 | * needs to be effective. | |
666 | */ | |
667 | try_to_free_buffers(page); | |
abfc3488 | 668 | goto rcu_unlock; |
62e1c553 | 669 | } |
abfc3488 | 670 | goto skip_unmap; |
62e1c553 SL |
671 | } |
672 | ||
dc386d4d | 673 | /* Establish migration ptes or remove ptes */ |
14fa31b8 | 674 | try_to_unmap(page, TTU_MIGRATION|TTU_IGNORE_MLOCK|TTU_IGNORE_ACCESS); |
dc386d4d | 675 | |
abfc3488 | 676 | skip_unmap: |
e6a1530d | 677 | if (!page_mapped(page)) |
3fe2011f | 678 | rc = move_to_new_page(newpage, page, remap_swapcache); |
e24f0b8f | 679 | |
3fe2011f | 680 | if (rc && remap_swapcache) |
e24f0b8f | 681 | remove_migration_ptes(page, page); |
dc386d4d | 682 | rcu_unlock: |
3f6c8272 MG |
683 | |
684 | /* Drop an anon_vma reference if we took one */ | |
7f60c214 | 685 | if (anon_vma && atomic_dec_and_lock(&anon_vma->external_refcount, &anon_vma->lock)) { |
3f6c8272 MG |
686 | int empty = list_empty(&anon_vma->head); |
687 | spin_unlock(&anon_vma->lock); | |
688 | if (empty) | |
689 | anon_vma_free(anon_vma); | |
690 | } | |
691 | ||
989f89c5 KH |
692 | if (rcu_locked) |
693 | rcu_read_unlock(); | |
01b1ae63 KH |
694 | uncharge: |
695 | if (!charge) | |
696 | mem_cgroup_end_migration(mem, page, newpage); | |
e24f0b8f CL |
697 | unlock: |
698 | unlock_page(page); | |
95a402c3 | 699 | |
e24f0b8f | 700 | if (rc != -EAGAIN) { |
aaa994b3 CL |
701 | /* |
702 | * A page that has been migrated has all references | |
703 | * removed and will be freed. A page that has not been | |
704 | * migrated will have kepts its references and be | |
705 | * restored. | |
706 | */ | |
707 | list_del(&page->lru); | |
a731286d | 708 | dec_zone_page_state(page, NR_ISOLATED_ANON + |
6c0b1351 | 709 | page_is_file_cache(page)); |
894bc310 | 710 | putback_lru_page(page); |
e24f0b8f | 711 | } |
95a402c3 CL |
712 | |
713 | move_newpage: | |
894bc310 | 714 | |
95a402c3 CL |
715 | /* |
716 | * Move the new page to the LRU. If migration was not successful | |
717 | * then this will free the page. | |
718 | */ | |
894bc310 LS |
719 | putback_lru_page(newpage); |
720 | ||
742755a1 CL |
721 | if (result) { |
722 | if (rc) | |
723 | *result = rc; | |
724 | else | |
725 | *result = page_to_nid(newpage); | |
726 | } | |
e24f0b8f CL |
727 | return rc; |
728 | } | |
729 | ||
b20a3503 CL |
730 | /* |
731 | * migrate_pages | |
732 | * | |
95a402c3 CL |
733 | * The function takes one list of pages to migrate and a function |
734 | * that determines from the page to be migrated and the private data | |
735 | * the target of the move and allocates the page. | |
b20a3503 CL |
736 | * |
737 | * The function returns after 10 attempts or if no pages | |
738 | * are movable anymore because to has become empty | |
aaa994b3 | 739 | * or no retryable pages exist anymore. All pages will be |
e9534b3f | 740 | * returned to the LRU or freed. |
b20a3503 | 741 | * |
95a402c3 | 742 | * Return: Number of pages not migrated or error code. |
b20a3503 | 743 | */ |
95a402c3 | 744 | int migrate_pages(struct list_head *from, |
62b61f61 | 745 | new_page_t get_new_page, unsigned long private, int offlining) |
b20a3503 | 746 | { |
e24f0b8f | 747 | int retry = 1; |
b20a3503 CL |
748 | int nr_failed = 0; |
749 | int pass = 0; | |
750 | struct page *page; | |
751 | struct page *page2; | |
752 | int swapwrite = current->flags & PF_SWAPWRITE; | |
753 | int rc; | |
754 | ||
755 | if (!swapwrite) | |
756 | current->flags |= PF_SWAPWRITE; | |
757 | ||
e24f0b8f CL |
758 | for(pass = 0; pass < 10 && retry; pass++) { |
759 | retry = 0; | |
b20a3503 | 760 | |
e24f0b8f | 761 | list_for_each_entry_safe(page, page2, from, lru) { |
e24f0b8f | 762 | cond_resched(); |
2d1db3b1 | 763 | |
95a402c3 | 764 | rc = unmap_and_move(get_new_page, private, |
62b61f61 | 765 | page, pass > 2, offlining); |
2d1db3b1 | 766 | |
e24f0b8f | 767 | switch(rc) { |
95a402c3 CL |
768 | case -ENOMEM: |
769 | goto out; | |
e24f0b8f | 770 | case -EAGAIN: |
2d1db3b1 | 771 | retry++; |
e24f0b8f CL |
772 | break; |
773 | case 0: | |
e24f0b8f CL |
774 | break; |
775 | default: | |
2d1db3b1 | 776 | /* Permanent failure */ |
2d1db3b1 | 777 | nr_failed++; |
e24f0b8f | 778 | break; |
2d1db3b1 | 779 | } |
b20a3503 CL |
780 | } |
781 | } | |
95a402c3 CL |
782 | rc = 0; |
783 | out: | |
b20a3503 CL |
784 | if (!swapwrite) |
785 | current->flags &= ~PF_SWAPWRITE; | |
786 | ||
aaa994b3 | 787 | putback_lru_pages(from); |
b20a3503 | 788 | |
95a402c3 CL |
789 | if (rc) |
790 | return rc; | |
b20a3503 | 791 | |
95a402c3 | 792 | return nr_failed + retry; |
b20a3503 | 793 | } |
95a402c3 | 794 | |
742755a1 CL |
795 | #ifdef CONFIG_NUMA |
796 | /* | |
797 | * Move a list of individual pages | |
798 | */ | |
799 | struct page_to_node { | |
800 | unsigned long addr; | |
801 | struct page *page; | |
802 | int node; | |
803 | int status; | |
804 | }; | |
805 | ||
806 | static struct page *new_page_node(struct page *p, unsigned long private, | |
807 | int **result) | |
808 | { | |
809 | struct page_to_node *pm = (struct page_to_node *)private; | |
810 | ||
811 | while (pm->node != MAX_NUMNODES && pm->page != p) | |
812 | pm++; | |
813 | ||
814 | if (pm->node == MAX_NUMNODES) | |
815 | return NULL; | |
816 | ||
817 | *result = &pm->status; | |
818 | ||
6484eb3e | 819 | return alloc_pages_exact_node(pm->node, |
769848c0 | 820 | GFP_HIGHUSER_MOVABLE | GFP_THISNODE, 0); |
742755a1 CL |
821 | } |
822 | ||
823 | /* | |
824 | * Move a set of pages as indicated in the pm array. The addr | |
825 | * field must be set to the virtual address of the page to be moved | |
826 | * and the node number must contain a valid target node. | |
5e9a0f02 | 827 | * The pm array ends with node = MAX_NUMNODES. |
742755a1 | 828 | */ |
5e9a0f02 BG |
829 | static int do_move_page_to_node_array(struct mm_struct *mm, |
830 | struct page_to_node *pm, | |
831 | int migrate_all) | |
742755a1 CL |
832 | { |
833 | int err; | |
834 | struct page_to_node *pp; | |
835 | LIST_HEAD(pagelist); | |
836 | ||
837 | down_read(&mm->mmap_sem); | |
838 | ||
839 | /* | |
840 | * Build a list of pages to migrate | |
841 | */ | |
742755a1 CL |
842 | for (pp = pm; pp->node != MAX_NUMNODES; pp++) { |
843 | struct vm_area_struct *vma; | |
844 | struct page *page; | |
845 | ||
742755a1 CL |
846 | err = -EFAULT; |
847 | vma = find_vma(mm, pp->addr); | |
0dc952dc | 848 | if (!vma || !vma_migratable(vma)) |
742755a1 CL |
849 | goto set_status; |
850 | ||
851 | page = follow_page(vma, pp->addr, FOLL_GET); | |
89f5b7da LT |
852 | |
853 | err = PTR_ERR(page); | |
854 | if (IS_ERR(page)) | |
855 | goto set_status; | |
856 | ||
742755a1 CL |
857 | err = -ENOENT; |
858 | if (!page) | |
859 | goto set_status; | |
860 | ||
62b61f61 HD |
861 | /* Use PageReserved to check for zero page */ |
862 | if (PageReserved(page) || PageKsm(page)) | |
742755a1 CL |
863 | goto put_and_set; |
864 | ||
865 | pp->page = page; | |
866 | err = page_to_nid(page); | |
867 | ||
868 | if (err == pp->node) | |
869 | /* | |
870 | * Node already in the right place | |
871 | */ | |
872 | goto put_and_set; | |
873 | ||
874 | err = -EACCES; | |
875 | if (page_mapcount(page) > 1 && | |
876 | !migrate_all) | |
877 | goto put_and_set; | |
878 | ||
62695a84 | 879 | err = isolate_lru_page(page); |
6d9c285a | 880 | if (!err) { |
62695a84 | 881 | list_add_tail(&page->lru, &pagelist); |
6d9c285a KM |
882 | inc_zone_page_state(page, NR_ISOLATED_ANON + |
883 | page_is_file_cache(page)); | |
884 | } | |
742755a1 CL |
885 | put_and_set: |
886 | /* | |
887 | * Either remove the duplicate refcount from | |
888 | * isolate_lru_page() or drop the page ref if it was | |
889 | * not isolated. | |
890 | */ | |
891 | put_page(page); | |
892 | set_status: | |
893 | pp->status = err; | |
894 | } | |
895 | ||
e78bbfa8 | 896 | err = 0; |
742755a1 CL |
897 | if (!list_empty(&pagelist)) |
898 | err = migrate_pages(&pagelist, new_page_node, | |
62b61f61 | 899 | (unsigned long)pm, 0); |
742755a1 CL |
900 | |
901 | up_read(&mm->mmap_sem); | |
902 | return err; | |
903 | } | |
904 | ||
5e9a0f02 BG |
905 | /* |
906 | * Migrate an array of page address onto an array of nodes and fill | |
907 | * the corresponding array of status. | |
908 | */ | |
909 | static int do_pages_move(struct mm_struct *mm, struct task_struct *task, | |
910 | unsigned long nr_pages, | |
911 | const void __user * __user *pages, | |
912 | const int __user *nodes, | |
913 | int __user *status, int flags) | |
914 | { | |
3140a227 | 915 | struct page_to_node *pm; |
5e9a0f02 | 916 | nodemask_t task_nodes; |
3140a227 BG |
917 | unsigned long chunk_nr_pages; |
918 | unsigned long chunk_start; | |
919 | int err; | |
5e9a0f02 BG |
920 | |
921 | task_nodes = cpuset_mems_allowed(task); | |
922 | ||
3140a227 BG |
923 | err = -ENOMEM; |
924 | pm = (struct page_to_node *)__get_free_page(GFP_KERNEL); | |
925 | if (!pm) | |
5e9a0f02 | 926 | goto out; |
35282a2d BG |
927 | |
928 | migrate_prep(); | |
929 | ||
5e9a0f02 | 930 | /* |
3140a227 BG |
931 | * Store a chunk of page_to_node array in a page, |
932 | * but keep the last one as a marker | |
5e9a0f02 | 933 | */ |
3140a227 | 934 | chunk_nr_pages = (PAGE_SIZE / sizeof(struct page_to_node)) - 1; |
5e9a0f02 | 935 | |
3140a227 BG |
936 | for (chunk_start = 0; |
937 | chunk_start < nr_pages; | |
938 | chunk_start += chunk_nr_pages) { | |
939 | int j; | |
5e9a0f02 | 940 | |
3140a227 BG |
941 | if (chunk_start + chunk_nr_pages > nr_pages) |
942 | chunk_nr_pages = nr_pages - chunk_start; | |
943 | ||
944 | /* fill the chunk pm with addrs and nodes from user-space */ | |
945 | for (j = 0; j < chunk_nr_pages; j++) { | |
946 | const void __user *p; | |
5e9a0f02 BG |
947 | int node; |
948 | ||
3140a227 BG |
949 | err = -EFAULT; |
950 | if (get_user(p, pages + j + chunk_start)) | |
951 | goto out_pm; | |
952 | pm[j].addr = (unsigned long) p; | |
953 | ||
954 | if (get_user(node, nodes + j + chunk_start)) | |
5e9a0f02 BG |
955 | goto out_pm; |
956 | ||
957 | err = -ENODEV; | |
6f5a55f1 LT |
958 | if (node < 0 || node >= MAX_NUMNODES) |
959 | goto out_pm; | |
960 | ||
5e9a0f02 BG |
961 | if (!node_state(node, N_HIGH_MEMORY)) |
962 | goto out_pm; | |
963 | ||
964 | err = -EACCES; | |
965 | if (!node_isset(node, task_nodes)) | |
966 | goto out_pm; | |
967 | ||
3140a227 BG |
968 | pm[j].node = node; |
969 | } | |
970 | ||
971 | /* End marker for this chunk */ | |
972 | pm[chunk_nr_pages].node = MAX_NUMNODES; | |
973 | ||
974 | /* Migrate this chunk */ | |
975 | err = do_move_page_to_node_array(mm, pm, | |
976 | flags & MPOL_MF_MOVE_ALL); | |
977 | if (err < 0) | |
978 | goto out_pm; | |
5e9a0f02 | 979 | |
5e9a0f02 | 980 | /* Return status information */ |
3140a227 BG |
981 | for (j = 0; j < chunk_nr_pages; j++) |
982 | if (put_user(pm[j].status, status + j + chunk_start)) { | |
5e9a0f02 | 983 | err = -EFAULT; |
3140a227 BG |
984 | goto out_pm; |
985 | } | |
986 | } | |
987 | err = 0; | |
5e9a0f02 BG |
988 | |
989 | out_pm: | |
3140a227 | 990 | free_page((unsigned long)pm); |
5e9a0f02 BG |
991 | out: |
992 | return err; | |
993 | } | |
994 | ||
742755a1 | 995 | /* |
2f007e74 | 996 | * Determine the nodes of an array of pages and store it in an array of status. |
742755a1 | 997 | */ |
80bba129 BG |
998 | static void do_pages_stat_array(struct mm_struct *mm, unsigned long nr_pages, |
999 | const void __user **pages, int *status) | |
742755a1 | 1000 | { |
2f007e74 | 1001 | unsigned long i; |
2f007e74 | 1002 | |
742755a1 CL |
1003 | down_read(&mm->mmap_sem); |
1004 | ||
2f007e74 | 1005 | for (i = 0; i < nr_pages; i++) { |
80bba129 | 1006 | unsigned long addr = (unsigned long)(*pages); |
742755a1 CL |
1007 | struct vm_area_struct *vma; |
1008 | struct page *page; | |
c095adbc | 1009 | int err = -EFAULT; |
2f007e74 BG |
1010 | |
1011 | vma = find_vma(mm, addr); | |
742755a1 CL |
1012 | if (!vma) |
1013 | goto set_status; | |
1014 | ||
2f007e74 | 1015 | page = follow_page(vma, addr, 0); |
89f5b7da LT |
1016 | |
1017 | err = PTR_ERR(page); | |
1018 | if (IS_ERR(page)) | |
1019 | goto set_status; | |
1020 | ||
742755a1 CL |
1021 | err = -ENOENT; |
1022 | /* Use PageReserved to check for zero page */ | |
62b61f61 | 1023 | if (!page || PageReserved(page) || PageKsm(page)) |
742755a1 CL |
1024 | goto set_status; |
1025 | ||
1026 | err = page_to_nid(page); | |
1027 | set_status: | |
80bba129 BG |
1028 | *status = err; |
1029 | ||
1030 | pages++; | |
1031 | status++; | |
1032 | } | |
1033 | ||
1034 | up_read(&mm->mmap_sem); | |
1035 | } | |
1036 | ||
1037 | /* | |
1038 | * Determine the nodes of a user array of pages and store it in | |
1039 | * a user array of status. | |
1040 | */ | |
1041 | static int do_pages_stat(struct mm_struct *mm, unsigned long nr_pages, | |
1042 | const void __user * __user *pages, | |
1043 | int __user *status) | |
1044 | { | |
1045 | #define DO_PAGES_STAT_CHUNK_NR 16 | |
1046 | const void __user *chunk_pages[DO_PAGES_STAT_CHUNK_NR]; | |
1047 | int chunk_status[DO_PAGES_STAT_CHUNK_NR]; | |
80bba129 | 1048 | |
87b8d1ad PA |
1049 | while (nr_pages) { |
1050 | unsigned long chunk_nr; | |
80bba129 | 1051 | |
87b8d1ad PA |
1052 | chunk_nr = nr_pages; |
1053 | if (chunk_nr > DO_PAGES_STAT_CHUNK_NR) | |
1054 | chunk_nr = DO_PAGES_STAT_CHUNK_NR; | |
1055 | ||
1056 | if (copy_from_user(chunk_pages, pages, chunk_nr * sizeof(*chunk_pages))) | |
1057 | break; | |
80bba129 BG |
1058 | |
1059 | do_pages_stat_array(mm, chunk_nr, chunk_pages, chunk_status); | |
1060 | ||
87b8d1ad PA |
1061 | if (copy_to_user(status, chunk_status, chunk_nr * sizeof(*status))) |
1062 | break; | |
742755a1 | 1063 | |
87b8d1ad PA |
1064 | pages += chunk_nr; |
1065 | status += chunk_nr; | |
1066 | nr_pages -= chunk_nr; | |
1067 | } | |
1068 | return nr_pages ? -EFAULT : 0; | |
742755a1 CL |
1069 | } |
1070 | ||
1071 | /* | |
1072 | * Move a list of pages in the address space of the currently executing | |
1073 | * process. | |
1074 | */ | |
938bb9f5 HC |
1075 | SYSCALL_DEFINE6(move_pages, pid_t, pid, unsigned long, nr_pages, |
1076 | const void __user * __user *, pages, | |
1077 | const int __user *, nodes, | |
1078 | int __user *, status, int, flags) | |
742755a1 | 1079 | { |
c69e8d9c | 1080 | const struct cred *cred = current_cred(), *tcred; |
742755a1 | 1081 | struct task_struct *task; |
742755a1 | 1082 | struct mm_struct *mm; |
5e9a0f02 | 1083 | int err; |
742755a1 CL |
1084 | |
1085 | /* Check flags */ | |
1086 | if (flags & ~(MPOL_MF_MOVE|MPOL_MF_MOVE_ALL)) | |
1087 | return -EINVAL; | |
1088 | ||
1089 | if ((flags & MPOL_MF_MOVE_ALL) && !capable(CAP_SYS_NICE)) | |
1090 | return -EPERM; | |
1091 | ||
1092 | /* Find the mm_struct */ | |
1093 | read_lock(&tasklist_lock); | |
228ebcbe | 1094 | task = pid ? find_task_by_vpid(pid) : current; |
742755a1 CL |
1095 | if (!task) { |
1096 | read_unlock(&tasklist_lock); | |
1097 | return -ESRCH; | |
1098 | } | |
1099 | mm = get_task_mm(task); | |
1100 | read_unlock(&tasklist_lock); | |
1101 | ||
1102 | if (!mm) | |
1103 | return -EINVAL; | |
1104 | ||
1105 | /* | |
1106 | * Check if this process has the right to modify the specified | |
1107 | * process. The right exists if the process has administrative | |
1108 | * capabilities, superuser privileges or the same | |
1109 | * userid as the target process. | |
1110 | */ | |
c69e8d9c DH |
1111 | rcu_read_lock(); |
1112 | tcred = __task_cred(task); | |
b6dff3ec DH |
1113 | if (cred->euid != tcred->suid && cred->euid != tcred->uid && |
1114 | cred->uid != tcred->suid && cred->uid != tcred->uid && | |
742755a1 | 1115 | !capable(CAP_SYS_NICE)) { |
c69e8d9c | 1116 | rcu_read_unlock(); |
742755a1 | 1117 | err = -EPERM; |
5e9a0f02 | 1118 | goto out; |
742755a1 | 1119 | } |
c69e8d9c | 1120 | rcu_read_unlock(); |
742755a1 | 1121 | |
86c3a764 DQ |
1122 | err = security_task_movememory(task); |
1123 | if (err) | |
5e9a0f02 | 1124 | goto out; |
86c3a764 | 1125 | |
5e9a0f02 BG |
1126 | if (nodes) { |
1127 | err = do_pages_move(mm, task, nr_pages, pages, nodes, status, | |
1128 | flags); | |
1129 | } else { | |
2f007e74 | 1130 | err = do_pages_stat(mm, nr_pages, pages, status); |
742755a1 CL |
1131 | } |
1132 | ||
742755a1 | 1133 | out: |
742755a1 CL |
1134 | mmput(mm); |
1135 | return err; | |
1136 | } | |
742755a1 | 1137 | |
7b2259b3 CL |
1138 | /* |
1139 | * Call migration functions in the vma_ops that may prepare | |
1140 | * memory in a vm for migration. migration functions may perform | |
1141 | * the migration for vmas that do not have an underlying page struct. | |
1142 | */ | |
1143 | int migrate_vmas(struct mm_struct *mm, const nodemask_t *to, | |
1144 | const nodemask_t *from, unsigned long flags) | |
1145 | { | |
1146 | struct vm_area_struct *vma; | |
1147 | int err = 0; | |
1148 | ||
1001c9fb | 1149 | for (vma = mm->mmap; vma && !err; vma = vma->vm_next) { |
7b2259b3 CL |
1150 | if (vma->vm_ops && vma->vm_ops->migrate) { |
1151 | err = vma->vm_ops->migrate(vma, to, from, flags); | |
1152 | if (err) | |
1153 | break; | |
1154 | } | |
1155 | } | |
1156 | return err; | |
1157 | } | |
83d1674a | 1158 | #endif |