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 | 37 | |
0d1836c3 MN |
38 | #include <asm/tlbflush.h> |
39 | ||
b20a3503 CL |
40 | #include "internal.h" |
41 | ||
b20a3503 CL |
42 | #define lru_to_page(_head) (list_entry((_head)->prev, struct page, lru)) |
43 | ||
b20a3503 | 44 | /* |
742755a1 | 45 | * migrate_prep() needs to be called before we start compiling a list of pages |
748446bb MG |
46 | * to be migrated using isolate_lru_page(). If scheduling work on other CPUs is |
47 | * undesirable, use migrate_prep_local() | |
b20a3503 CL |
48 | */ |
49 | int migrate_prep(void) | |
50 | { | |
b20a3503 CL |
51 | /* |
52 | * Clear the LRU lists so pages can be isolated. | |
53 | * Note that pages may be moved off the LRU after we have | |
54 | * drained them. Those pages will fail to migrate like other | |
55 | * pages that may be busy. | |
56 | */ | |
57 | lru_add_drain_all(); | |
58 | ||
59 | return 0; | |
60 | } | |
61 | ||
748446bb MG |
62 | /* Do the necessary work of migrate_prep but not if it involves other CPUs */ |
63 | int migrate_prep_local(void) | |
64 | { | |
65 | lru_add_drain(); | |
66 | ||
67 | return 0; | |
68 | } | |
69 | ||
b20a3503 | 70 | /* |
894bc310 LS |
71 | * Add isolated pages on the list back to the LRU under page lock |
72 | * to avoid leaking evictable pages back onto unevictable list. | |
b20a3503 | 73 | */ |
e13861d8 | 74 | void putback_lru_pages(struct list_head *l) |
b20a3503 CL |
75 | { |
76 | struct page *page; | |
77 | struct page *page2; | |
b20a3503 CL |
78 | |
79 | list_for_each_entry_safe(page, page2, l, lru) { | |
e24f0b8f | 80 | list_del(&page->lru); |
a731286d | 81 | dec_zone_page_state(page, NR_ISOLATED_ANON + |
6c0b1351 | 82 | page_is_file_cache(page)); |
894bc310 | 83 | putback_lru_page(page); |
b20a3503 | 84 | } |
b20a3503 CL |
85 | } |
86 | ||
0697212a CL |
87 | /* |
88 | * Restore a potential migration pte to a working pte entry | |
89 | */ | |
e9995ef9 HD |
90 | static int remove_migration_pte(struct page *new, struct vm_area_struct *vma, |
91 | unsigned long addr, void *old) | |
0697212a CL |
92 | { |
93 | struct mm_struct *mm = vma->vm_mm; | |
94 | swp_entry_t entry; | |
95 | pgd_t *pgd; | |
96 | pud_t *pud; | |
97 | pmd_t *pmd; | |
98 | pte_t *ptep, pte; | |
99 | spinlock_t *ptl; | |
100 | ||
290408d4 NH |
101 | if (unlikely(PageHuge(new))) { |
102 | ptep = huge_pte_offset(mm, addr); | |
103 | if (!ptep) | |
104 | goto out; | |
105 | ptl = &mm->page_table_lock; | |
106 | } else { | |
107 | pgd = pgd_offset(mm, addr); | |
108 | if (!pgd_present(*pgd)) | |
109 | goto out; | |
0697212a | 110 | |
290408d4 NH |
111 | pud = pud_offset(pgd, addr); |
112 | if (!pud_present(*pud)) | |
113 | goto out; | |
0697212a | 114 | |
290408d4 | 115 | pmd = pmd_offset(pud, addr); |
500d65d4 AA |
116 | if (pmd_trans_huge(*pmd)) |
117 | goto out; | |
290408d4 NH |
118 | if (!pmd_present(*pmd)) |
119 | goto out; | |
0697212a | 120 | |
290408d4 | 121 | ptep = pte_offset_map(pmd, addr); |
0697212a | 122 | |
290408d4 NH |
123 | if (!is_swap_pte(*ptep)) { |
124 | pte_unmap(ptep); | |
125 | goto out; | |
126 | } | |
127 | ||
128 | ptl = pte_lockptr(mm, pmd); | |
129 | } | |
0697212a | 130 | |
0697212a CL |
131 | spin_lock(ptl); |
132 | pte = *ptep; | |
133 | if (!is_swap_pte(pte)) | |
e9995ef9 | 134 | goto unlock; |
0697212a CL |
135 | |
136 | entry = pte_to_swp_entry(pte); | |
137 | ||
e9995ef9 HD |
138 | if (!is_migration_entry(entry) || |
139 | migration_entry_to_page(entry) != old) | |
140 | goto unlock; | |
0697212a | 141 | |
0697212a CL |
142 | get_page(new); |
143 | pte = pte_mkold(mk_pte(new, vma->vm_page_prot)); | |
144 | if (is_write_migration_entry(entry)) | |
145 | pte = pte_mkwrite(pte); | |
3ef8fd7f | 146 | #ifdef CONFIG_HUGETLB_PAGE |
290408d4 NH |
147 | if (PageHuge(new)) |
148 | pte = pte_mkhuge(pte); | |
3ef8fd7f | 149 | #endif |
97ee0524 | 150 | flush_cache_page(vma, addr, pte_pfn(pte)); |
0697212a | 151 | set_pte_at(mm, addr, ptep, pte); |
04e62a29 | 152 | |
290408d4 NH |
153 | if (PageHuge(new)) { |
154 | if (PageAnon(new)) | |
155 | hugepage_add_anon_rmap(new, vma, addr); | |
156 | else | |
157 | page_dup_rmap(new); | |
158 | } else if (PageAnon(new)) | |
04e62a29 CL |
159 | page_add_anon_rmap(new, vma, addr); |
160 | else | |
161 | page_add_file_rmap(new); | |
162 | ||
163 | /* No need to invalidate - it was non-present before */ | |
4b3073e1 | 164 | update_mmu_cache(vma, addr, ptep); |
e9995ef9 | 165 | unlock: |
0697212a | 166 | pte_unmap_unlock(ptep, ptl); |
e9995ef9 HD |
167 | out: |
168 | return SWAP_AGAIN; | |
0697212a CL |
169 | } |
170 | ||
04e62a29 CL |
171 | /* |
172 | * Get rid of all migration entries and replace them by | |
173 | * references to the indicated page. | |
174 | */ | |
175 | static void remove_migration_ptes(struct page *old, struct page *new) | |
176 | { | |
e9995ef9 | 177 | rmap_walk(new, remove_migration_pte, old); |
04e62a29 CL |
178 | } |
179 | ||
0697212a CL |
180 | /* |
181 | * Something used the pte of a page under migration. We need to | |
182 | * get to the page and wait until migration is finished. | |
183 | * When we return from this function the fault will be retried. | |
184 | * | |
185 | * This function is called from do_swap_page(). | |
186 | */ | |
187 | void migration_entry_wait(struct mm_struct *mm, pmd_t *pmd, | |
188 | unsigned long address) | |
189 | { | |
190 | pte_t *ptep, pte; | |
191 | spinlock_t *ptl; | |
192 | swp_entry_t entry; | |
193 | struct page *page; | |
194 | ||
195 | ptep = pte_offset_map_lock(mm, pmd, address, &ptl); | |
196 | pte = *ptep; | |
197 | if (!is_swap_pte(pte)) | |
198 | goto out; | |
199 | ||
200 | entry = pte_to_swp_entry(pte); | |
201 | if (!is_migration_entry(entry)) | |
202 | goto out; | |
203 | ||
204 | page = migration_entry_to_page(entry); | |
205 | ||
e286781d NP |
206 | /* |
207 | * Once radix-tree replacement of page migration started, page_count | |
208 | * *must* be zero. And, we don't want to call wait_on_page_locked() | |
209 | * against a page without get_page(). | |
210 | * So, we use get_page_unless_zero(), here. Even failed, page fault | |
211 | * will occur again. | |
212 | */ | |
213 | if (!get_page_unless_zero(page)) | |
214 | goto out; | |
0697212a CL |
215 | pte_unmap_unlock(ptep, ptl); |
216 | wait_on_page_locked(page); | |
217 | put_page(page); | |
218 | return; | |
219 | out: | |
220 | pte_unmap_unlock(ptep, ptl); | |
221 | } | |
222 | ||
b20a3503 | 223 | /* |
c3fcf8a5 | 224 | * Replace the page in the mapping. |
5b5c7120 CL |
225 | * |
226 | * The number of remaining references must be: | |
227 | * 1 for anonymous pages without a mapping | |
228 | * 2 for pages with a mapping | |
266cf658 | 229 | * 3 for pages with a mapping and PagePrivate/PagePrivate2 set. |
b20a3503 | 230 | */ |
2d1db3b1 CL |
231 | static int migrate_page_move_mapping(struct address_space *mapping, |
232 | struct page *newpage, struct page *page) | |
b20a3503 | 233 | { |
e286781d | 234 | int expected_count; |
7cf9c2c7 | 235 | void **pslot; |
b20a3503 | 236 | |
6c5240ae | 237 | if (!mapping) { |
0e8c7d0f | 238 | /* Anonymous page without mapping */ |
6c5240ae CL |
239 | if (page_count(page) != 1) |
240 | return -EAGAIN; | |
241 | return 0; | |
242 | } | |
243 | ||
19fd6231 | 244 | spin_lock_irq(&mapping->tree_lock); |
b20a3503 | 245 | |
7cf9c2c7 NP |
246 | pslot = radix_tree_lookup_slot(&mapping->page_tree, |
247 | page_index(page)); | |
b20a3503 | 248 | |
edcf4748 | 249 | expected_count = 2 + page_has_private(page); |
e286781d | 250 | if (page_count(page) != expected_count || |
29c1f677 | 251 | radix_tree_deref_slot_protected(pslot, &mapping->tree_lock) != page) { |
19fd6231 | 252 | spin_unlock_irq(&mapping->tree_lock); |
e23ca00b | 253 | return -EAGAIN; |
b20a3503 CL |
254 | } |
255 | ||
e286781d | 256 | if (!page_freeze_refs(page, expected_count)) { |
19fd6231 | 257 | spin_unlock_irq(&mapping->tree_lock); |
e286781d NP |
258 | return -EAGAIN; |
259 | } | |
260 | ||
b20a3503 CL |
261 | /* |
262 | * Now we know that no one else is looking at the page. | |
b20a3503 | 263 | */ |
7cf9c2c7 | 264 | get_page(newpage); /* add cache reference */ |
b20a3503 CL |
265 | if (PageSwapCache(page)) { |
266 | SetPageSwapCache(newpage); | |
267 | set_page_private(newpage, page_private(page)); | |
268 | } | |
269 | ||
7cf9c2c7 NP |
270 | radix_tree_replace_slot(pslot, newpage); |
271 | ||
e286781d | 272 | page_unfreeze_refs(page, expected_count); |
7cf9c2c7 NP |
273 | /* |
274 | * Drop cache reference from old page. | |
275 | * We know this isn't the last reference. | |
276 | */ | |
b20a3503 | 277 | __put_page(page); |
7cf9c2c7 | 278 | |
0e8c7d0f CL |
279 | /* |
280 | * If moved to a different zone then also account | |
281 | * the page for that zone. Other VM counters will be | |
282 | * taken care of when we establish references to the | |
283 | * new page and drop references to the old page. | |
284 | * | |
285 | * Note that anonymous pages are accounted for | |
286 | * via NR_FILE_PAGES and NR_ANON_PAGES if they | |
287 | * are mapped to swap space. | |
288 | */ | |
289 | __dec_zone_page_state(page, NR_FILE_PAGES); | |
290 | __inc_zone_page_state(newpage, NR_FILE_PAGES); | |
4b02108a KM |
291 | if (PageSwapBacked(page)) { |
292 | __dec_zone_page_state(page, NR_SHMEM); | |
293 | __inc_zone_page_state(newpage, NR_SHMEM); | |
294 | } | |
19fd6231 | 295 | spin_unlock_irq(&mapping->tree_lock); |
b20a3503 CL |
296 | |
297 | return 0; | |
298 | } | |
b20a3503 | 299 | |
290408d4 NH |
300 | /* |
301 | * The expected number of remaining references is the same as that | |
302 | * of migrate_page_move_mapping(). | |
303 | */ | |
304 | int migrate_huge_page_move_mapping(struct address_space *mapping, | |
305 | struct page *newpage, struct page *page) | |
306 | { | |
307 | int expected_count; | |
308 | void **pslot; | |
309 | ||
310 | if (!mapping) { | |
311 | if (page_count(page) != 1) | |
312 | return -EAGAIN; | |
313 | return 0; | |
314 | } | |
315 | ||
316 | spin_lock_irq(&mapping->tree_lock); | |
317 | ||
318 | pslot = radix_tree_lookup_slot(&mapping->page_tree, | |
319 | page_index(page)); | |
320 | ||
321 | expected_count = 2 + page_has_private(page); | |
322 | if (page_count(page) != expected_count || | |
29c1f677 | 323 | radix_tree_deref_slot_protected(pslot, &mapping->tree_lock) != page) { |
290408d4 NH |
324 | spin_unlock_irq(&mapping->tree_lock); |
325 | return -EAGAIN; | |
326 | } | |
327 | ||
328 | if (!page_freeze_refs(page, expected_count)) { | |
329 | spin_unlock_irq(&mapping->tree_lock); | |
330 | return -EAGAIN; | |
331 | } | |
332 | ||
333 | get_page(newpage); | |
334 | ||
335 | radix_tree_replace_slot(pslot, newpage); | |
336 | ||
337 | page_unfreeze_refs(page, expected_count); | |
338 | ||
339 | __put_page(page); | |
340 | ||
341 | spin_unlock_irq(&mapping->tree_lock); | |
342 | return 0; | |
343 | } | |
344 | ||
b20a3503 CL |
345 | /* |
346 | * Copy the page to its new location | |
347 | */ | |
290408d4 | 348 | void migrate_page_copy(struct page *newpage, struct page *page) |
b20a3503 | 349 | { |
290408d4 NH |
350 | if (PageHuge(page)) |
351 | copy_huge_page(newpage, page); | |
352 | else | |
353 | copy_highpage(newpage, page); | |
b20a3503 CL |
354 | |
355 | if (PageError(page)) | |
356 | SetPageError(newpage); | |
357 | if (PageReferenced(page)) | |
358 | SetPageReferenced(newpage); | |
359 | if (PageUptodate(page)) | |
360 | SetPageUptodate(newpage); | |
894bc310 LS |
361 | if (TestClearPageActive(page)) { |
362 | VM_BUG_ON(PageUnevictable(page)); | |
b20a3503 | 363 | SetPageActive(newpage); |
418b27ef LS |
364 | } else if (TestClearPageUnevictable(page)) |
365 | SetPageUnevictable(newpage); | |
b20a3503 CL |
366 | if (PageChecked(page)) |
367 | SetPageChecked(newpage); | |
368 | if (PageMappedToDisk(page)) | |
369 | SetPageMappedToDisk(newpage); | |
370 | ||
371 | if (PageDirty(page)) { | |
372 | clear_page_dirty_for_io(page); | |
3a902c5f NP |
373 | /* |
374 | * Want to mark the page and the radix tree as dirty, and | |
375 | * redo the accounting that clear_page_dirty_for_io undid, | |
376 | * but we can't use set_page_dirty because that function | |
377 | * is actually a signal that all of the page has become dirty. | |
378 | * Wheras only part of our page may be dirty. | |
379 | */ | |
380 | __set_page_dirty_nobuffers(newpage); | |
b20a3503 CL |
381 | } |
382 | ||
b291f000 | 383 | mlock_migrate_page(newpage, page); |
e9995ef9 | 384 | ksm_migrate_page(newpage, page); |
b291f000 | 385 | |
b20a3503 | 386 | ClearPageSwapCache(page); |
b20a3503 CL |
387 | ClearPagePrivate(page); |
388 | set_page_private(page, 0); | |
389 | page->mapping = NULL; | |
390 | ||
391 | /* | |
392 | * If any waiters have accumulated on the new page then | |
393 | * wake them up. | |
394 | */ | |
395 | if (PageWriteback(newpage)) | |
396 | end_page_writeback(newpage); | |
397 | } | |
b20a3503 | 398 | |
1d8b85cc CL |
399 | /************************************************************ |
400 | * Migration functions | |
401 | ***********************************************************/ | |
402 | ||
403 | /* Always fail migration. Used for mappings that are not movable */ | |
2d1db3b1 CL |
404 | int fail_migrate_page(struct address_space *mapping, |
405 | struct page *newpage, struct page *page) | |
1d8b85cc CL |
406 | { |
407 | return -EIO; | |
408 | } | |
409 | EXPORT_SYMBOL(fail_migrate_page); | |
410 | ||
b20a3503 CL |
411 | /* |
412 | * Common logic to directly migrate a single page suitable for | |
266cf658 | 413 | * pages that do not use PagePrivate/PagePrivate2. |
b20a3503 CL |
414 | * |
415 | * Pages are locked upon entry and exit. | |
416 | */ | |
2d1db3b1 CL |
417 | int migrate_page(struct address_space *mapping, |
418 | struct page *newpage, struct page *page) | |
b20a3503 CL |
419 | { |
420 | int rc; | |
421 | ||
422 | BUG_ON(PageWriteback(page)); /* Writeback must be complete */ | |
423 | ||
2d1db3b1 | 424 | rc = migrate_page_move_mapping(mapping, newpage, page); |
b20a3503 CL |
425 | |
426 | if (rc) | |
427 | return rc; | |
428 | ||
429 | migrate_page_copy(newpage, page); | |
b20a3503 CL |
430 | return 0; |
431 | } | |
432 | EXPORT_SYMBOL(migrate_page); | |
433 | ||
9361401e | 434 | #ifdef CONFIG_BLOCK |
1d8b85cc CL |
435 | /* |
436 | * Migration function for pages with buffers. This function can only be used | |
437 | * if the underlying filesystem guarantees that no other references to "page" | |
438 | * exist. | |
439 | */ | |
2d1db3b1 CL |
440 | int buffer_migrate_page(struct address_space *mapping, |
441 | struct page *newpage, struct page *page) | |
1d8b85cc | 442 | { |
1d8b85cc CL |
443 | struct buffer_head *bh, *head; |
444 | int rc; | |
445 | ||
1d8b85cc | 446 | if (!page_has_buffers(page)) |
2d1db3b1 | 447 | return migrate_page(mapping, newpage, page); |
1d8b85cc CL |
448 | |
449 | head = page_buffers(page); | |
450 | ||
2d1db3b1 | 451 | rc = migrate_page_move_mapping(mapping, newpage, page); |
1d8b85cc CL |
452 | |
453 | if (rc) | |
454 | return rc; | |
455 | ||
456 | bh = head; | |
457 | do { | |
458 | get_bh(bh); | |
459 | lock_buffer(bh); | |
460 | bh = bh->b_this_page; | |
461 | ||
462 | } while (bh != head); | |
463 | ||
464 | ClearPagePrivate(page); | |
465 | set_page_private(newpage, page_private(page)); | |
466 | set_page_private(page, 0); | |
467 | put_page(page); | |
468 | get_page(newpage); | |
469 | ||
470 | bh = head; | |
471 | do { | |
472 | set_bh_page(bh, newpage, bh_offset(bh)); | |
473 | bh = bh->b_this_page; | |
474 | ||
475 | } while (bh != head); | |
476 | ||
477 | SetPagePrivate(newpage); | |
478 | ||
479 | migrate_page_copy(newpage, page); | |
480 | ||
481 | bh = head; | |
482 | do { | |
483 | unlock_buffer(bh); | |
484 | put_bh(bh); | |
485 | bh = bh->b_this_page; | |
486 | ||
487 | } while (bh != head); | |
488 | ||
489 | return 0; | |
490 | } | |
491 | EXPORT_SYMBOL(buffer_migrate_page); | |
9361401e | 492 | #endif |
1d8b85cc | 493 | |
04e62a29 CL |
494 | /* |
495 | * Writeback a page to clean the dirty state | |
496 | */ | |
497 | static int writeout(struct address_space *mapping, struct page *page) | |
8351a6e4 | 498 | { |
04e62a29 CL |
499 | struct writeback_control wbc = { |
500 | .sync_mode = WB_SYNC_NONE, | |
501 | .nr_to_write = 1, | |
502 | .range_start = 0, | |
503 | .range_end = LLONG_MAX, | |
04e62a29 CL |
504 | .for_reclaim = 1 |
505 | }; | |
506 | int rc; | |
507 | ||
508 | if (!mapping->a_ops->writepage) | |
509 | /* No write method for the address space */ | |
510 | return -EINVAL; | |
511 | ||
512 | if (!clear_page_dirty_for_io(page)) | |
513 | /* Someone else already triggered a write */ | |
514 | return -EAGAIN; | |
515 | ||
8351a6e4 | 516 | /* |
04e62a29 CL |
517 | * A dirty page may imply that the underlying filesystem has |
518 | * the page on some queue. So the page must be clean for | |
519 | * migration. Writeout may mean we loose the lock and the | |
520 | * page state is no longer what we checked for earlier. | |
521 | * At this point we know that the migration attempt cannot | |
522 | * be successful. | |
8351a6e4 | 523 | */ |
04e62a29 | 524 | remove_migration_ptes(page, page); |
8351a6e4 | 525 | |
04e62a29 | 526 | rc = mapping->a_ops->writepage(page, &wbc); |
8351a6e4 | 527 | |
04e62a29 CL |
528 | if (rc != AOP_WRITEPAGE_ACTIVATE) |
529 | /* unlocked. Relock */ | |
530 | lock_page(page); | |
531 | ||
bda8550d | 532 | return (rc < 0) ? -EIO : -EAGAIN; |
04e62a29 CL |
533 | } |
534 | ||
535 | /* | |
536 | * Default handling if a filesystem does not provide a migration function. | |
537 | */ | |
538 | static int fallback_migrate_page(struct address_space *mapping, | |
539 | struct page *newpage, struct page *page) | |
540 | { | |
541 | if (PageDirty(page)) | |
542 | return writeout(mapping, page); | |
8351a6e4 CL |
543 | |
544 | /* | |
545 | * Buffers may be managed in a filesystem specific way. | |
546 | * We must have no buffers or drop them. | |
547 | */ | |
266cf658 | 548 | if (page_has_private(page) && |
8351a6e4 CL |
549 | !try_to_release_page(page, GFP_KERNEL)) |
550 | return -EAGAIN; | |
551 | ||
552 | return migrate_page(mapping, newpage, page); | |
553 | } | |
554 | ||
e24f0b8f CL |
555 | /* |
556 | * Move a page to a newly allocated page | |
557 | * The page is locked and all ptes have been successfully removed. | |
558 | * | |
559 | * The new page will have replaced the old page if this function | |
560 | * is successful. | |
894bc310 LS |
561 | * |
562 | * Return value: | |
563 | * < 0 - error code | |
564 | * == 0 - success | |
e24f0b8f | 565 | */ |
3fe2011f MG |
566 | static int move_to_new_page(struct page *newpage, struct page *page, |
567 | int remap_swapcache) | |
e24f0b8f CL |
568 | { |
569 | struct address_space *mapping; | |
570 | int rc; | |
571 | ||
572 | /* | |
573 | * Block others from accessing the page when we get around to | |
574 | * establishing additional references. We are the only one | |
575 | * holding a reference to the new page at this point. | |
576 | */ | |
529ae9aa | 577 | if (!trylock_page(newpage)) |
e24f0b8f CL |
578 | BUG(); |
579 | ||
580 | /* Prepare mapping for the new page.*/ | |
581 | newpage->index = page->index; | |
582 | newpage->mapping = page->mapping; | |
b2e18538 RR |
583 | if (PageSwapBacked(page)) |
584 | SetPageSwapBacked(newpage); | |
e24f0b8f CL |
585 | |
586 | mapping = page_mapping(page); | |
587 | if (!mapping) | |
588 | rc = migrate_page(mapping, newpage, page); | |
589 | else if (mapping->a_ops->migratepage) | |
590 | /* | |
591 | * Most pages have a mapping and most filesystems | |
592 | * should provide a migration function. Anonymous | |
593 | * pages are part of swap space which also has its | |
594 | * own migration function. This is the most common | |
595 | * path for page migration. | |
596 | */ | |
597 | rc = mapping->a_ops->migratepage(mapping, | |
598 | newpage, page); | |
599 | else | |
600 | rc = fallback_migrate_page(mapping, newpage, page); | |
601 | ||
3fe2011f | 602 | if (rc) { |
e24f0b8f | 603 | newpage->mapping = NULL; |
3fe2011f MG |
604 | } else { |
605 | if (remap_swapcache) | |
606 | remove_migration_ptes(page, newpage); | |
607 | } | |
e24f0b8f CL |
608 | |
609 | unlock_page(newpage); | |
610 | ||
611 | return rc; | |
612 | } | |
613 | ||
614 | /* | |
615 | * Obtain the lock on page, remove all ptes and migrate the page | |
616 | * to the newly allocated page in newpage. | |
617 | */ | |
95a402c3 | 618 | static int unmap_and_move(new_page_t get_new_page, unsigned long private, |
7f0f2496 | 619 | struct page *page, int force, bool offlining, bool sync) |
e24f0b8f CL |
620 | { |
621 | int rc = 0; | |
742755a1 CL |
622 | int *result = NULL; |
623 | struct page *newpage = get_new_page(page, private, &result); | |
3fe2011f | 624 | int remap_swapcache = 1; |
ae41be37 | 625 | int charge = 0; |
e00e4316 | 626 | struct mem_cgroup *mem = NULL; |
3f6c8272 | 627 | struct anon_vma *anon_vma = NULL; |
95a402c3 CL |
628 | |
629 | if (!newpage) | |
630 | return -ENOMEM; | |
e24f0b8f | 631 | |
894bc310 | 632 | if (page_count(page) == 1) { |
e24f0b8f | 633 | /* page was freed from under us. So we are done. */ |
95a402c3 | 634 | goto move_newpage; |
894bc310 | 635 | } |
500d65d4 AA |
636 | if (unlikely(PageTransHuge(page))) |
637 | if (unlikely(split_huge_page(page))) | |
638 | goto move_newpage; | |
e24f0b8f | 639 | |
e8589cc1 | 640 | /* prepare cgroup just returns 0 or -ENOMEM */ |
e24f0b8f | 641 | rc = -EAGAIN; |
01b1ae63 | 642 | |
529ae9aa | 643 | if (!trylock_page(page)) { |
e24f0b8f | 644 | if (!force) |
95a402c3 | 645 | goto move_newpage; |
3e7d3449 MG |
646 | |
647 | /* | |
648 | * It's not safe for direct compaction to call lock_page. | |
649 | * For example, during page readahead pages are added locked | |
650 | * to the LRU. Later, when the IO completes the pages are | |
651 | * marked uptodate and unlocked. However, the queueing | |
652 | * could be merging multiple pages for one bio (e.g. | |
653 | * mpage_readpages). If an allocation happens for the | |
654 | * second or third page, the process can end up locking | |
655 | * the same page twice and deadlocking. Rather than | |
656 | * trying to be clever about what pages can be locked, | |
657 | * avoid the use of lock_page for direct compaction | |
658 | * altogether. | |
659 | */ | |
660 | if (current->flags & PF_MEMALLOC) | |
661 | goto move_newpage; | |
662 | ||
e24f0b8f CL |
663 | lock_page(page); |
664 | } | |
665 | ||
62b61f61 HD |
666 | /* |
667 | * Only memory hotplug's offline_pages() caller has locked out KSM, | |
668 | * and can safely migrate a KSM page. The other cases have skipped | |
669 | * PageKsm along with PageReserved - but it is only now when we have | |
670 | * the page lock that we can be certain it will not go KSM beneath us | |
671 | * (KSM will not upgrade a page from PageAnon to PageKsm when it sees | |
672 | * its pagecount raised, but only here do we take the page lock which | |
673 | * serializes that). | |
674 | */ | |
675 | if (PageKsm(page) && !offlining) { | |
676 | rc = -EBUSY; | |
677 | goto unlock; | |
678 | } | |
679 | ||
01b1ae63 | 680 | /* charge against new page */ |
ac39cf8c | 681 | charge = mem_cgroup_prepare_migration(page, newpage, &mem); |
01b1ae63 KH |
682 | if (charge == -ENOMEM) { |
683 | rc = -ENOMEM; | |
684 | goto unlock; | |
685 | } | |
686 | BUG_ON(charge); | |
687 | ||
e24f0b8f | 688 | if (PageWriteback(page)) { |
77f1fe6b | 689 | if (!force || !sync) |
01b1ae63 | 690 | goto uncharge; |
e24f0b8f CL |
691 | wait_on_page_writeback(page); |
692 | } | |
e24f0b8f | 693 | /* |
dc386d4d KH |
694 | * By try_to_unmap(), page->mapcount goes down to 0 here. In this case, |
695 | * we cannot notice that anon_vma is freed while we migrates a page. | |
1ce82b69 | 696 | * This get_anon_vma() delays freeing anon_vma pointer until the end |
dc386d4d | 697 | * of migration. File cache pages are no problem because of page_lock() |
989f89c5 KH |
698 | * File Caches may use write_page() or lock_page() in migration, then, |
699 | * just care Anon page here. | |
dc386d4d | 700 | */ |
989f89c5 | 701 | if (PageAnon(page)) { |
1ce82b69 HD |
702 | /* |
703 | * Only page_lock_anon_vma() understands the subtleties of | |
704 | * getting a hold on an anon_vma from outside one of its mms. | |
705 | */ | |
706 | anon_vma = page_lock_anon_vma(page); | |
707 | if (anon_vma) { | |
708 | /* | |
709 | * Take a reference count on the anon_vma if the | |
710 | * page is mapped so that it is guaranteed to | |
711 | * exist when the page is remapped later | |
712 | */ | |
713 | get_anon_vma(anon_vma); | |
714 | page_unlock_anon_vma(anon_vma); | |
715 | } else if (PageSwapCache(page)) { | |
3fe2011f MG |
716 | /* |
717 | * We cannot be sure that the anon_vma of an unmapped | |
718 | * swapcache page is safe to use because we don't | |
719 | * know in advance if the VMA that this page belonged | |
720 | * to still exists. If the VMA and others sharing the | |
721 | * data have been freed, then the anon_vma could | |
722 | * already be invalid. | |
723 | * | |
724 | * To avoid this possibility, swapcache pages get | |
725 | * migrated but are not remapped when migration | |
726 | * completes | |
727 | */ | |
728 | remap_swapcache = 0; | |
729 | } else { | |
1ce82b69 | 730 | goto uncharge; |
3fe2011f | 731 | } |
989f89c5 | 732 | } |
62e1c553 | 733 | |
dc386d4d | 734 | /* |
62e1c553 SL |
735 | * Corner case handling: |
736 | * 1. When a new swap-cache page is read into, it is added to the LRU | |
737 | * and treated as swapcache but it has no rmap yet. | |
738 | * Calling try_to_unmap() against a page->mapping==NULL page will | |
739 | * trigger a BUG. So handle it here. | |
740 | * 2. An orphaned page (see truncate_complete_page) might have | |
741 | * fs-private metadata. The page can be picked up due to memory | |
742 | * offlining. Everywhere else except page reclaim, the page is | |
743 | * invisible to the vm, so the page can not be migrated. So try to | |
744 | * free the metadata, so the page can be freed. | |
e24f0b8f | 745 | */ |
62e1c553 | 746 | if (!page->mapping) { |
1ce82b69 HD |
747 | VM_BUG_ON(PageAnon(page)); |
748 | if (page_has_private(page)) { | |
62e1c553 | 749 | try_to_free_buffers(page); |
1ce82b69 | 750 | goto uncharge; |
62e1c553 | 751 | } |
abfc3488 | 752 | goto skip_unmap; |
62e1c553 SL |
753 | } |
754 | ||
dc386d4d | 755 | /* Establish migration ptes or remove ptes */ |
14fa31b8 | 756 | try_to_unmap(page, TTU_MIGRATION|TTU_IGNORE_MLOCK|TTU_IGNORE_ACCESS); |
dc386d4d | 757 | |
abfc3488 | 758 | skip_unmap: |
e6a1530d | 759 | if (!page_mapped(page)) |
3fe2011f | 760 | rc = move_to_new_page(newpage, page, remap_swapcache); |
e24f0b8f | 761 | |
3fe2011f | 762 | if (rc && remap_swapcache) |
e24f0b8f | 763 | remove_migration_ptes(page, page); |
3f6c8272 MG |
764 | |
765 | /* Drop an anon_vma reference if we took one */ | |
76545066 RR |
766 | if (anon_vma) |
767 | drop_anon_vma(anon_vma); | |
3f6c8272 | 768 | |
01b1ae63 KH |
769 | uncharge: |
770 | if (!charge) | |
50de1dd9 | 771 | mem_cgroup_end_migration(mem, page, newpage, rc == 0); |
e24f0b8f CL |
772 | unlock: |
773 | unlock_page(page); | |
95a402c3 | 774 | |
57fc4a5e | 775 | move_newpage: |
e24f0b8f | 776 | if (rc != -EAGAIN) { |
aaa994b3 CL |
777 | /* |
778 | * A page that has been migrated has all references | |
779 | * removed and will be freed. A page that has not been | |
780 | * migrated will have kepts its references and be | |
781 | * restored. | |
782 | */ | |
783 | list_del(&page->lru); | |
a731286d | 784 | dec_zone_page_state(page, NR_ISOLATED_ANON + |
6c0b1351 | 785 | page_is_file_cache(page)); |
894bc310 | 786 | putback_lru_page(page); |
e24f0b8f | 787 | } |
95a402c3 | 788 | |
95a402c3 CL |
789 | /* |
790 | * Move the new page to the LRU. If migration was not successful | |
791 | * then this will free the page. | |
792 | */ | |
894bc310 LS |
793 | putback_lru_page(newpage); |
794 | ||
742755a1 CL |
795 | if (result) { |
796 | if (rc) | |
797 | *result = rc; | |
798 | else | |
799 | *result = page_to_nid(newpage); | |
800 | } | |
e24f0b8f CL |
801 | return rc; |
802 | } | |
803 | ||
290408d4 NH |
804 | /* |
805 | * Counterpart of unmap_and_move_page() for hugepage migration. | |
806 | * | |
807 | * This function doesn't wait the completion of hugepage I/O | |
808 | * because there is no race between I/O and migration for hugepage. | |
809 | * Note that currently hugepage I/O occurs only in direct I/O | |
810 | * where no lock is held and PG_writeback is irrelevant, | |
811 | * and writeback status of all subpages are counted in the reference | |
812 | * count of the head page (i.e. if all subpages of a 2MB hugepage are | |
813 | * under direct I/O, the reference of the head page is 512 and a bit more.) | |
814 | * This means that when we try to migrate hugepage whose subpages are | |
815 | * doing direct I/O, some references remain after try_to_unmap() and | |
816 | * hugepage migration fails without data corruption. | |
817 | * | |
818 | * There is also no race when direct I/O is issued on the page under migration, | |
819 | * because then pte is replaced with migration swap entry and direct I/O code | |
820 | * will wait in the page fault for migration to complete. | |
821 | */ | |
822 | static int unmap_and_move_huge_page(new_page_t get_new_page, | |
823 | unsigned long private, struct page *hpage, | |
7f0f2496 | 824 | int force, bool offlining, bool sync) |
290408d4 NH |
825 | { |
826 | int rc = 0; | |
827 | int *result = NULL; | |
828 | struct page *new_hpage = get_new_page(hpage, private, &result); | |
290408d4 NH |
829 | struct anon_vma *anon_vma = NULL; |
830 | ||
831 | if (!new_hpage) | |
832 | return -ENOMEM; | |
833 | ||
834 | rc = -EAGAIN; | |
835 | ||
836 | if (!trylock_page(hpage)) { | |
77f1fe6b | 837 | if (!force || !sync) |
290408d4 NH |
838 | goto out; |
839 | lock_page(hpage); | |
840 | } | |
841 | ||
842 | if (PageAnon(hpage)) { | |
fd4a4663 HD |
843 | anon_vma = page_lock_anon_vma(hpage); |
844 | if (anon_vma) { | |
845 | get_anon_vma(anon_vma); | |
846 | page_unlock_anon_vma(anon_vma); | |
290408d4 NH |
847 | } |
848 | } | |
849 | ||
850 | try_to_unmap(hpage, TTU_MIGRATION|TTU_IGNORE_MLOCK|TTU_IGNORE_ACCESS); | |
851 | ||
852 | if (!page_mapped(hpage)) | |
853 | rc = move_to_new_page(new_hpage, hpage, 1); | |
854 | ||
855 | if (rc) | |
856 | remove_migration_ptes(hpage, hpage); | |
857 | ||
fd4a4663 HD |
858 | if (anon_vma) |
859 | drop_anon_vma(anon_vma); | |
290408d4 NH |
860 | out: |
861 | unlock_page(hpage); | |
862 | ||
863 | if (rc != -EAGAIN) { | |
864 | list_del(&hpage->lru); | |
865 | put_page(hpage); | |
866 | } | |
867 | ||
868 | put_page(new_hpage); | |
869 | ||
870 | if (result) { | |
871 | if (rc) | |
872 | *result = rc; | |
873 | else | |
874 | *result = page_to_nid(new_hpage); | |
875 | } | |
876 | return rc; | |
877 | } | |
878 | ||
b20a3503 CL |
879 | /* |
880 | * migrate_pages | |
881 | * | |
95a402c3 CL |
882 | * The function takes one list of pages to migrate and a function |
883 | * that determines from the page to be migrated and the private data | |
884 | * the target of the move and allocates the page. | |
b20a3503 CL |
885 | * |
886 | * The function returns after 10 attempts or if no pages | |
887 | * are movable anymore because to has become empty | |
cf608ac1 MK |
888 | * or no retryable pages exist anymore. |
889 | * Caller should call putback_lru_pages to return pages to the LRU | |
28bd6578 | 890 | * or free list only if ret != 0. |
b20a3503 | 891 | * |
95a402c3 | 892 | * Return: Number of pages not migrated or error code. |
b20a3503 | 893 | */ |
95a402c3 | 894 | int migrate_pages(struct list_head *from, |
7f0f2496 | 895 | new_page_t get_new_page, unsigned long private, bool offlining, |
77f1fe6b | 896 | bool sync) |
b20a3503 | 897 | { |
e24f0b8f | 898 | int retry = 1; |
b20a3503 CL |
899 | int nr_failed = 0; |
900 | int pass = 0; | |
901 | struct page *page; | |
902 | struct page *page2; | |
903 | int swapwrite = current->flags & PF_SWAPWRITE; | |
904 | int rc; | |
905 | ||
906 | if (!swapwrite) | |
907 | current->flags |= PF_SWAPWRITE; | |
908 | ||
e24f0b8f CL |
909 | for(pass = 0; pass < 10 && retry; pass++) { |
910 | retry = 0; | |
b20a3503 | 911 | |
e24f0b8f | 912 | list_for_each_entry_safe(page, page2, from, lru) { |
e24f0b8f | 913 | cond_resched(); |
2d1db3b1 | 914 | |
95a402c3 | 915 | rc = unmap_and_move(get_new_page, private, |
77f1fe6b MG |
916 | page, pass > 2, offlining, |
917 | sync); | |
2d1db3b1 | 918 | |
e24f0b8f | 919 | switch(rc) { |
95a402c3 CL |
920 | case -ENOMEM: |
921 | goto out; | |
e24f0b8f | 922 | case -EAGAIN: |
2d1db3b1 | 923 | retry++; |
e24f0b8f CL |
924 | break; |
925 | case 0: | |
e24f0b8f CL |
926 | break; |
927 | default: | |
2d1db3b1 | 928 | /* Permanent failure */ |
2d1db3b1 | 929 | nr_failed++; |
e24f0b8f | 930 | break; |
2d1db3b1 | 931 | } |
b20a3503 CL |
932 | } |
933 | } | |
95a402c3 CL |
934 | rc = 0; |
935 | out: | |
b20a3503 CL |
936 | if (!swapwrite) |
937 | current->flags &= ~PF_SWAPWRITE; | |
938 | ||
95a402c3 CL |
939 | if (rc) |
940 | return rc; | |
b20a3503 | 941 | |
95a402c3 | 942 | return nr_failed + retry; |
b20a3503 | 943 | } |
95a402c3 | 944 | |
290408d4 | 945 | int migrate_huge_pages(struct list_head *from, |
7f0f2496 | 946 | new_page_t get_new_page, unsigned long private, bool offlining, |
77f1fe6b | 947 | bool sync) |
290408d4 NH |
948 | { |
949 | int retry = 1; | |
950 | int nr_failed = 0; | |
951 | int pass = 0; | |
952 | struct page *page; | |
953 | struct page *page2; | |
954 | int rc; | |
955 | ||
956 | for (pass = 0; pass < 10 && retry; pass++) { | |
957 | retry = 0; | |
958 | ||
959 | list_for_each_entry_safe(page, page2, from, lru) { | |
960 | cond_resched(); | |
961 | ||
962 | rc = unmap_and_move_huge_page(get_new_page, | |
77f1fe6b MG |
963 | private, page, pass > 2, offlining, |
964 | sync); | |
290408d4 NH |
965 | |
966 | switch(rc) { | |
967 | case -ENOMEM: | |
968 | goto out; | |
969 | case -EAGAIN: | |
970 | retry++; | |
971 | break; | |
972 | case 0: | |
973 | break; | |
974 | default: | |
975 | /* Permanent failure */ | |
976 | nr_failed++; | |
977 | break; | |
978 | } | |
979 | } | |
980 | } | |
981 | rc = 0; | |
982 | out: | |
290408d4 NH |
983 | if (rc) |
984 | return rc; | |
985 | ||
986 | return nr_failed + retry; | |
987 | } | |
988 | ||
742755a1 CL |
989 | #ifdef CONFIG_NUMA |
990 | /* | |
991 | * Move a list of individual pages | |
992 | */ | |
993 | struct page_to_node { | |
994 | unsigned long addr; | |
995 | struct page *page; | |
996 | int node; | |
997 | int status; | |
998 | }; | |
999 | ||
1000 | static struct page *new_page_node(struct page *p, unsigned long private, | |
1001 | int **result) | |
1002 | { | |
1003 | struct page_to_node *pm = (struct page_to_node *)private; | |
1004 | ||
1005 | while (pm->node != MAX_NUMNODES && pm->page != p) | |
1006 | pm++; | |
1007 | ||
1008 | if (pm->node == MAX_NUMNODES) | |
1009 | return NULL; | |
1010 | ||
1011 | *result = &pm->status; | |
1012 | ||
6484eb3e | 1013 | return alloc_pages_exact_node(pm->node, |
769848c0 | 1014 | GFP_HIGHUSER_MOVABLE | GFP_THISNODE, 0); |
742755a1 CL |
1015 | } |
1016 | ||
1017 | /* | |
1018 | * Move a set of pages as indicated in the pm array. The addr | |
1019 | * field must be set to the virtual address of the page to be moved | |
1020 | * and the node number must contain a valid target node. | |
5e9a0f02 | 1021 | * The pm array ends with node = MAX_NUMNODES. |
742755a1 | 1022 | */ |
5e9a0f02 BG |
1023 | static int do_move_page_to_node_array(struct mm_struct *mm, |
1024 | struct page_to_node *pm, | |
1025 | int migrate_all) | |
742755a1 CL |
1026 | { |
1027 | int err; | |
1028 | struct page_to_node *pp; | |
1029 | LIST_HEAD(pagelist); | |
1030 | ||
1031 | down_read(&mm->mmap_sem); | |
1032 | ||
1033 | /* | |
1034 | * Build a list of pages to migrate | |
1035 | */ | |
742755a1 CL |
1036 | for (pp = pm; pp->node != MAX_NUMNODES; pp++) { |
1037 | struct vm_area_struct *vma; | |
1038 | struct page *page; | |
1039 | ||
742755a1 CL |
1040 | err = -EFAULT; |
1041 | vma = find_vma(mm, pp->addr); | |
70384dc6 | 1042 | if (!vma || pp->addr < vma->vm_start || !vma_migratable(vma)) |
742755a1 CL |
1043 | goto set_status; |
1044 | ||
500d65d4 | 1045 | page = follow_page(vma, pp->addr, FOLL_GET|FOLL_SPLIT); |
89f5b7da LT |
1046 | |
1047 | err = PTR_ERR(page); | |
1048 | if (IS_ERR(page)) | |
1049 | goto set_status; | |
1050 | ||
742755a1 CL |
1051 | err = -ENOENT; |
1052 | if (!page) | |
1053 | goto set_status; | |
1054 | ||
62b61f61 HD |
1055 | /* Use PageReserved to check for zero page */ |
1056 | if (PageReserved(page) || PageKsm(page)) | |
742755a1 CL |
1057 | goto put_and_set; |
1058 | ||
1059 | pp->page = page; | |
1060 | err = page_to_nid(page); | |
1061 | ||
1062 | if (err == pp->node) | |
1063 | /* | |
1064 | * Node already in the right place | |
1065 | */ | |
1066 | goto put_and_set; | |
1067 | ||
1068 | err = -EACCES; | |
1069 | if (page_mapcount(page) > 1 && | |
1070 | !migrate_all) | |
1071 | goto put_and_set; | |
1072 | ||
62695a84 | 1073 | err = isolate_lru_page(page); |
6d9c285a | 1074 | if (!err) { |
62695a84 | 1075 | list_add_tail(&page->lru, &pagelist); |
6d9c285a KM |
1076 | inc_zone_page_state(page, NR_ISOLATED_ANON + |
1077 | page_is_file_cache(page)); | |
1078 | } | |
742755a1 CL |
1079 | put_and_set: |
1080 | /* | |
1081 | * Either remove the duplicate refcount from | |
1082 | * isolate_lru_page() or drop the page ref if it was | |
1083 | * not isolated. | |
1084 | */ | |
1085 | put_page(page); | |
1086 | set_status: | |
1087 | pp->status = err; | |
1088 | } | |
1089 | ||
e78bbfa8 | 1090 | err = 0; |
cf608ac1 | 1091 | if (!list_empty(&pagelist)) { |
742755a1 | 1092 | err = migrate_pages(&pagelist, new_page_node, |
77f1fe6b | 1093 | (unsigned long)pm, 0, true); |
cf608ac1 MK |
1094 | if (err) |
1095 | putback_lru_pages(&pagelist); | |
1096 | } | |
742755a1 CL |
1097 | |
1098 | up_read(&mm->mmap_sem); | |
1099 | return err; | |
1100 | } | |
1101 | ||
5e9a0f02 BG |
1102 | /* |
1103 | * Migrate an array of page address onto an array of nodes and fill | |
1104 | * the corresponding array of status. | |
1105 | */ | |
1106 | static int do_pages_move(struct mm_struct *mm, struct task_struct *task, | |
1107 | unsigned long nr_pages, | |
1108 | const void __user * __user *pages, | |
1109 | const int __user *nodes, | |
1110 | int __user *status, int flags) | |
1111 | { | |
3140a227 | 1112 | struct page_to_node *pm; |
5e9a0f02 | 1113 | nodemask_t task_nodes; |
3140a227 BG |
1114 | unsigned long chunk_nr_pages; |
1115 | unsigned long chunk_start; | |
1116 | int err; | |
5e9a0f02 BG |
1117 | |
1118 | task_nodes = cpuset_mems_allowed(task); | |
1119 | ||
3140a227 BG |
1120 | err = -ENOMEM; |
1121 | pm = (struct page_to_node *)__get_free_page(GFP_KERNEL); | |
1122 | if (!pm) | |
5e9a0f02 | 1123 | goto out; |
35282a2d BG |
1124 | |
1125 | migrate_prep(); | |
1126 | ||
5e9a0f02 | 1127 | /* |
3140a227 BG |
1128 | * Store a chunk of page_to_node array in a page, |
1129 | * but keep the last one as a marker | |
5e9a0f02 | 1130 | */ |
3140a227 | 1131 | chunk_nr_pages = (PAGE_SIZE / sizeof(struct page_to_node)) - 1; |
5e9a0f02 | 1132 | |
3140a227 BG |
1133 | for (chunk_start = 0; |
1134 | chunk_start < nr_pages; | |
1135 | chunk_start += chunk_nr_pages) { | |
1136 | int j; | |
5e9a0f02 | 1137 | |
3140a227 BG |
1138 | if (chunk_start + chunk_nr_pages > nr_pages) |
1139 | chunk_nr_pages = nr_pages - chunk_start; | |
1140 | ||
1141 | /* fill the chunk pm with addrs and nodes from user-space */ | |
1142 | for (j = 0; j < chunk_nr_pages; j++) { | |
1143 | const void __user *p; | |
5e9a0f02 BG |
1144 | int node; |
1145 | ||
3140a227 BG |
1146 | err = -EFAULT; |
1147 | if (get_user(p, pages + j + chunk_start)) | |
1148 | goto out_pm; | |
1149 | pm[j].addr = (unsigned long) p; | |
1150 | ||
1151 | if (get_user(node, nodes + j + chunk_start)) | |
5e9a0f02 BG |
1152 | goto out_pm; |
1153 | ||
1154 | err = -ENODEV; | |
6f5a55f1 LT |
1155 | if (node < 0 || node >= MAX_NUMNODES) |
1156 | goto out_pm; | |
1157 | ||
5e9a0f02 BG |
1158 | if (!node_state(node, N_HIGH_MEMORY)) |
1159 | goto out_pm; | |
1160 | ||
1161 | err = -EACCES; | |
1162 | if (!node_isset(node, task_nodes)) | |
1163 | goto out_pm; | |
1164 | ||
3140a227 BG |
1165 | pm[j].node = node; |
1166 | } | |
1167 | ||
1168 | /* End marker for this chunk */ | |
1169 | pm[chunk_nr_pages].node = MAX_NUMNODES; | |
1170 | ||
1171 | /* Migrate this chunk */ | |
1172 | err = do_move_page_to_node_array(mm, pm, | |
1173 | flags & MPOL_MF_MOVE_ALL); | |
1174 | if (err < 0) | |
1175 | goto out_pm; | |
5e9a0f02 | 1176 | |
5e9a0f02 | 1177 | /* Return status information */ |
3140a227 BG |
1178 | for (j = 0; j < chunk_nr_pages; j++) |
1179 | if (put_user(pm[j].status, status + j + chunk_start)) { | |
5e9a0f02 | 1180 | err = -EFAULT; |
3140a227 BG |
1181 | goto out_pm; |
1182 | } | |
1183 | } | |
1184 | err = 0; | |
5e9a0f02 BG |
1185 | |
1186 | out_pm: | |
3140a227 | 1187 | free_page((unsigned long)pm); |
5e9a0f02 BG |
1188 | out: |
1189 | return err; | |
1190 | } | |
1191 | ||
742755a1 | 1192 | /* |
2f007e74 | 1193 | * Determine the nodes of an array of pages and store it in an array of status. |
742755a1 | 1194 | */ |
80bba129 BG |
1195 | static void do_pages_stat_array(struct mm_struct *mm, unsigned long nr_pages, |
1196 | const void __user **pages, int *status) | |
742755a1 | 1197 | { |
2f007e74 | 1198 | unsigned long i; |
2f007e74 | 1199 | |
742755a1 CL |
1200 | down_read(&mm->mmap_sem); |
1201 | ||
2f007e74 | 1202 | for (i = 0; i < nr_pages; i++) { |
80bba129 | 1203 | unsigned long addr = (unsigned long)(*pages); |
742755a1 CL |
1204 | struct vm_area_struct *vma; |
1205 | struct page *page; | |
c095adbc | 1206 | int err = -EFAULT; |
2f007e74 BG |
1207 | |
1208 | vma = find_vma(mm, addr); | |
70384dc6 | 1209 | if (!vma || addr < vma->vm_start) |
742755a1 CL |
1210 | goto set_status; |
1211 | ||
2f007e74 | 1212 | page = follow_page(vma, addr, 0); |
89f5b7da LT |
1213 | |
1214 | err = PTR_ERR(page); | |
1215 | if (IS_ERR(page)) | |
1216 | goto set_status; | |
1217 | ||
742755a1 CL |
1218 | err = -ENOENT; |
1219 | /* Use PageReserved to check for zero page */ | |
62b61f61 | 1220 | if (!page || PageReserved(page) || PageKsm(page)) |
742755a1 CL |
1221 | goto set_status; |
1222 | ||
1223 | err = page_to_nid(page); | |
1224 | set_status: | |
80bba129 BG |
1225 | *status = err; |
1226 | ||
1227 | pages++; | |
1228 | status++; | |
1229 | } | |
1230 | ||
1231 | up_read(&mm->mmap_sem); | |
1232 | } | |
1233 | ||
1234 | /* | |
1235 | * Determine the nodes of a user array of pages and store it in | |
1236 | * a user array of status. | |
1237 | */ | |
1238 | static int do_pages_stat(struct mm_struct *mm, unsigned long nr_pages, | |
1239 | const void __user * __user *pages, | |
1240 | int __user *status) | |
1241 | { | |
1242 | #define DO_PAGES_STAT_CHUNK_NR 16 | |
1243 | const void __user *chunk_pages[DO_PAGES_STAT_CHUNK_NR]; | |
1244 | int chunk_status[DO_PAGES_STAT_CHUNK_NR]; | |
80bba129 | 1245 | |
87b8d1ad PA |
1246 | while (nr_pages) { |
1247 | unsigned long chunk_nr; | |
80bba129 | 1248 | |
87b8d1ad PA |
1249 | chunk_nr = nr_pages; |
1250 | if (chunk_nr > DO_PAGES_STAT_CHUNK_NR) | |
1251 | chunk_nr = DO_PAGES_STAT_CHUNK_NR; | |
1252 | ||
1253 | if (copy_from_user(chunk_pages, pages, chunk_nr * sizeof(*chunk_pages))) | |
1254 | break; | |
80bba129 BG |
1255 | |
1256 | do_pages_stat_array(mm, chunk_nr, chunk_pages, chunk_status); | |
1257 | ||
87b8d1ad PA |
1258 | if (copy_to_user(status, chunk_status, chunk_nr * sizeof(*status))) |
1259 | break; | |
742755a1 | 1260 | |
87b8d1ad PA |
1261 | pages += chunk_nr; |
1262 | status += chunk_nr; | |
1263 | nr_pages -= chunk_nr; | |
1264 | } | |
1265 | return nr_pages ? -EFAULT : 0; | |
742755a1 CL |
1266 | } |
1267 | ||
1268 | /* | |
1269 | * Move a list of pages in the address space of the currently executing | |
1270 | * process. | |
1271 | */ | |
938bb9f5 HC |
1272 | SYSCALL_DEFINE6(move_pages, pid_t, pid, unsigned long, nr_pages, |
1273 | const void __user * __user *, pages, | |
1274 | const int __user *, nodes, | |
1275 | int __user *, status, int, flags) | |
742755a1 | 1276 | { |
c69e8d9c | 1277 | const struct cred *cred = current_cred(), *tcred; |
742755a1 | 1278 | struct task_struct *task; |
742755a1 | 1279 | struct mm_struct *mm; |
5e9a0f02 | 1280 | int err; |
742755a1 CL |
1281 | |
1282 | /* Check flags */ | |
1283 | if (flags & ~(MPOL_MF_MOVE|MPOL_MF_MOVE_ALL)) | |
1284 | return -EINVAL; | |
1285 | ||
1286 | if ((flags & MPOL_MF_MOVE_ALL) && !capable(CAP_SYS_NICE)) | |
1287 | return -EPERM; | |
1288 | ||
1289 | /* Find the mm_struct */ | |
a879bf58 | 1290 | rcu_read_lock(); |
228ebcbe | 1291 | task = pid ? find_task_by_vpid(pid) : current; |
742755a1 | 1292 | if (!task) { |
a879bf58 | 1293 | rcu_read_unlock(); |
742755a1 CL |
1294 | return -ESRCH; |
1295 | } | |
1296 | mm = get_task_mm(task); | |
a879bf58 | 1297 | rcu_read_unlock(); |
742755a1 CL |
1298 | |
1299 | if (!mm) | |
1300 | return -EINVAL; | |
1301 | ||
1302 | /* | |
1303 | * Check if this process has the right to modify the specified | |
1304 | * process. The right exists if the process has administrative | |
1305 | * capabilities, superuser privileges or the same | |
1306 | * userid as the target process. | |
1307 | */ | |
c69e8d9c DH |
1308 | rcu_read_lock(); |
1309 | tcred = __task_cred(task); | |
b6dff3ec DH |
1310 | if (cred->euid != tcred->suid && cred->euid != tcred->uid && |
1311 | cred->uid != tcred->suid && cred->uid != tcred->uid && | |
742755a1 | 1312 | !capable(CAP_SYS_NICE)) { |
c69e8d9c | 1313 | rcu_read_unlock(); |
742755a1 | 1314 | err = -EPERM; |
5e9a0f02 | 1315 | goto out; |
742755a1 | 1316 | } |
c69e8d9c | 1317 | rcu_read_unlock(); |
742755a1 | 1318 | |
86c3a764 DQ |
1319 | err = security_task_movememory(task); |
1320 | if (err) | |
5e9a0f02 | 1321 | goto out; |
86c3a764 | 1322 | |
5e9a0f02 BG |
1323 | if (nodes) { |
1324 | err = do_pages_move(mm, task, nr_pages, pages, nodes, status, | |
1325 | flags); | |
1326 | } else { | |
2f007e74 | 1327 | err = do_pages_stat(mm, nr_pages, pages, status); |
742755a1 CL |
1328 | } |
1329 | ||
742755a1 | 1330 | out: |
742755a1 CL |
1331 | mmput(mm); |
1332 | return err; | |
1333 | } | |
742755a1 | 1334 | |
7b2259b3 CL |
1335 | /* |
1336 | * Call migration functions in the vma_ops that may prepare | |
1337 | * memory in a vm for migration. migration functions may perform | |
1338 | * the migration for vmas that do not have an underlying page struct. | |
1339 | */ | |
1340 | int migrate_vmas(struct mm_struct *mm, const nodemask_t *to, | |
1341 | const nodemask_t *from, unsigned long flags) | |
1342 | { | |
1343 | struct vm_area_struct *vma; | |
1344 | int err = 0; | |
1345 | ||
1001c9fb | 1346 | for (vma = mm->mmap; vma && !err; vma = vma->vm_next) { |
7b2259b3 CL |
1347 | if (vma->vm_ops && vma->vm_ops->migrate) { |
1348 | err = vma->vm_ops->migrate(vma, to, from, flags); | |
1349 | if (err) | |
1350 | break; | |
1351 | } | |
1352 | } | |
1353 | return err; | |
1354 | } | |
83d1674a | 1355 | #endif |