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> |
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); | |
3ef8fd7f | 142 | #ifdef CONFIG_HUGETLB_PAGE |
290408d4 NH |
143 | if (PageHuge(new)) |
144 | pte = pte_mkhuge(pte); | |
3ef8fd7f | 145 | #endif |
97ee0524 | 146 | flush_cache_page(vma, addr, pte_pfn(pte)); |
0697212a | 147 | set_pte_at(mm, addr, ptep, pte); |
04e62a29 | 148 | |
290408d4 NH |
149 | if (PageHuge(new)) { |
150 | if (PageAnon(new)) | |
151 | hugepage_add_anon_rmap(new, vma, addr); | |
152 | else | |
153 | page_dup_rmap(new); | |
154 | } else if (PageAnon(new)) | |
04e62a29 CL |
155 | page_add_anon_rmap(new, vma, addr); |
156 | else | |
157 | page_add_file_rmap(new); | |
158 | ||
159 | /* No need to invalidate - it was non-present before */ | |
4b3073e1 | 160 | update_mmu_cache(vma, addr, ptep); |
e9995ef9 | 161 | unlock: |
0697212a | 162 | pte_unmap_unlock(ptep, ptl); |
e9995ef9 HD |
163 | out: |
164 | return SWAP_AGAIN; | |
0697212a CL |
165 | } |
166 | ||
04e62a29 CL |
167 | /* |
168 | * Get rid of all migration entries and replace them by | |
169 | * references to the indicated page. | |
170 | */ | |
171 | static void remove_migration_ptes(struct page *old, struct page *new) | |
172 | { | |
e9995ef9 | 173 | rmap_walk(new, remove_migration_pte, old); |
04e62a29 CL |
174 | } |
175 | ||
0697212a CL |
176 | /* |
177 | * Something used the pte of a page under migration. We need to | |
178 | * get to the page and wait until migration is finished. | |
179 | * When we return from this function the fault will be retried. | |
180 | * | |
181 | * This function is called from do_swap_page(). | |
182 | */ | |
183 | void migration_entry_wait(struct mm_struct *mm, pmd_t *pmd, | |
184 | unsigned long address) | |
185 | { | |
186 | pte_t *ptep, pte; | |
187 | spinlock_t *ptl; | |
188 | swp_entry_t entry; | |
189 | struct page *page; | |
190 | ||
191 | ptep = pte_offset_map_lock(mm, pmd, address, &ptl); | |
192 | pte = *ptep; | |
193 | if (!is_swap_pte(pte)) | |
194 | goto out; | |
195 | ||
196 | entry = pte_to_swp_entry(pte); | |
197 | if (!is_migration_entry(entry)) | |
198 | goto out; | |
199 | ||
200 | page = migration_entry_to_page(entry); | |
201 | ||
e286781d NP |
202 | /* |
203 | * Once radix-tree replacement of page migration started, page_count | |
204 | * *must* be zero. And, we don't want to call wait_on_page_locked() | |
205 | * against a page without get_page(). | |
206 | * So, we use get_page_unless_zero(), here. Even failed, page fault | |
207 | * will occur again. | |
208 | */ | |
209 | if (!get_page_unless_zero(page)) | |
210 | goto out; | |
0697212a CL |
211 | pte_unmap_unlock(ptep, ptl); |
212 | wait_on_page_locked(page); | |
213 | put_page(page); | |
214 | return; | |
215 | out: | |
216 | pte_unmap_unlock(ptep, ptl); | |
217 | } | |
218 | ||
b20a3503 | 219 | /* |
c3fcf8a5 | 220 | * Replace the page in the mapping. |
5b5c7120 CL |
221 | * |
222 | * The number of remaining references must be: | |
223 | * 1 for anonymous pages without a mapping | |
224 | * 2 for pages with a mapping | |
266cf658 | 225 | * 3 for pages with a mapping and PagePrivate/PagePrivate2 set. |
b20a3503 | 226 | */ |
2d1db3b1 CL |
227 | static int migrate_page_move_mapping(struct address_space *mapping, |
228 | struct page *newpage, struct page *page) | |
b20a3503 | 229 | { |
e286781d | 230 | int expected_count; |
7cf9c2c7 | 231 | void **pslot; |
b20a3503 | 232 | |
6c5240ae | 233 | if (!mapping) { |
0e8c7d0f | 234 | /* Anonymous page without mapping */ |
6c5240ae CL |
235 | if (page_count(page) != 1) |
236 | return -EAGAIN; | |
237 | return 0; | |
238 | } | |
239 | ||
19fd6231 | 240 | spin_lock_irq(&mapping->tree_lock); |
b20a3503 | 241 | |
7cf9c2c7 NP |
242 | pslot = radix_tree_lookup_slot(&mapping->page_tree, |
243 | page_index(page)); | |
b20a3503 | 244 | |
edcf4748 | 245 | expected_count = 2 + page_has_private(page); |
e286781d | 246 | if (page_count(page) != expected_count || |
7cf9c2c7 | 247 | (struct page *)radix_tree_deref_slot(pslot) != page) { |
19fd6231 | 248 | spin_unlock_irq(&mapping->tree_lock); |
e23ca00b | 249 | return -EAGAIN; |
b20a3503 CL |
250 | } |
251 | ||
e286781d | 252 | if (!page_freeze_refs(page, expected_count)) { |
19fd6231 | 253 | spin_unlock_irq(&mapping->tree_lock); |
e286781d NP |
254 | return -EAGAIN; |
255 | } | |
256 | ||
b20a3503 CL |
257 | /* |
258 | * Now we know that no one else is looking at the page. | |
b20a3503 | 259 | */ |
7cf9c2c7 | 260 | get_page(newpage); /* add cache reference */ |
b20a3503 CL |
261 | if (PageSwapCache(page)) { |
262 | SetPageSwapCache(newpage); | |
263 | set_page_private(newpage, page_private(page)); | |
264 | } | |
265 | ||
7cf9c2c7 NP |
266 | radix_tree_replace_slot(pslot, newpage); |
267 | ||
e286781d | 268 | page_unfreeze_refs(page, expected_count); |
7cf9c2c7 NP |
269 | /* |
270 | * Drop cache reference from old page. | |
271 | * We know this isn't the last reference. | |
272 | */ | |
b20a3503 | 273 | __put_page(page); |
7cf9c2c7 | 274 | |
0e8c7d0f CL |
275 | /* |
276 | * If moved to a different zone then also account | |
277 | * the page for that zone. Other VM counters will be | |
278 | * taken care of when we establish references to the | |
279 | * new page and drop references to the old page. | |
280 | * | |
281 | * Note that anonymous pages are accounted for | |
282 | * via NR_FILE_PAGES and NR_ANON_PAGES if they | |
283 | * are mapped to swap space. | |
284 | */ | |
285 | __dec_zone_page_state(page, NR_FILE_PAGES); | |
286 | __inc_zone_page_state(newpage, NR_FILE_PAGES); | |
4b02108a KM |
287 | if (PageSwapBacked(page)) { |
288 | __dec_zone_page_state(page, NR_SHMEM); | |
289 | __inc_zone_page_state(newpage, NR_SHMEM); | |
290 | } | |
19fd6231 | 291 | spin_unlock_irq(&mapping->tree_lock); |
b20a3503 CL |
292 | |
293 | return 0; | |
294 | } | |
b20a3503 | 295 | |
290408d4 NH |
296 | /* |
297 | * The expected number of remaining references is the same as that | |
298 | * of migrate_page_move_mapping(). | |
299 | */ | |
300 | int migrate_huge_page_move_mapping(struct address_space *mapping, | |
301 | struct page *newpage, struct page *page) | |
302 | { | |
303 | int expected_count; | |
304 | void **pslot; | |
305 | ||
306 | if (!mapping) { | |
307 | if (page_count(page) != 1) | |
308 | return -EAGAIN; | |
309 | return 0; | |
310 | } | |
311 | ||
312 | spin_lock_irq(&mapping->tree_lock); | |
313 | ||
314 | pslot = radix_tree_lookup_slot(&mapping->page_tree, | |
315 | page_index(page)); | |
316 | ||
317 | expected_count = 2 + page_has_private(page); | |
318 | if (page_count(page) != expected_count || | |
319 | (struct page *)radix_tree_deref_slot(pslot) != page) { | |
320 | spin_unlock_irq(&mapping->tree_lock); | |
321 | return -EAGAIN; | |
322 | } | |
323 | ||
324 | if (!page_freeze_refs(page, expected_count)) { | |
325 | spin_unlock_irq(&mapping->tree_lock); | |
326 | return -EAGAIN; | |
327 | } | |
328 | ||
329 | get_page(newpage); | |
330 | ||
331 | radix_tree_replace_slot(pslot, newpage); | |
332 | ||
333 | page_unfreeze_refs(page, expected_count); | |
334 | ||
335 | __put_page(page); | |
336 | ||
337 | spin_unlock_irq(&mapping->tree_lock); | |
338 | return 0; | |
339 | } | |
340 | ||
b20a3503 CL |
341 | /* |
342 | * Copy the page to its new location | |
343 | */ | |
290408d4 | 344 | void migrate_page_copy(struct page *newpage, struct page *page) |
b20a3503 | 345 | { |
290408d4 NH |
346 | if (PageHuge(page)) |
347 | copy_huge_page(newpage, page); | |
348 | else | |
349 | copy_highpage(newpage, page); | |
b20a3503 CL |
350 | |
351 | if (PageError(page)) | |
352 | SetPageError(newpage); | |
353 | if (PageReferenced(page)) | |
354 | SetPageReferenced(newpage); | |
355 | if (PageUptodate(page)) | |
356 | SetPageUptodate(newpage); | |
894bc310 LS |
357 | if (TestClearPageActive(page)) { |
358 | VM_BUG_ON(PageUnevictable(page)); | |
b20a3503 | 359 | SetPageActive(newpage); |
418b27ef LS |
360 | } else if (TestClearPageUnevictable(page)) |
361 | SetPageUnevictable(newpage); | |
b20a3503 CL |
362 | if (PageChecked(page)) |
363 | SetPageChecked(newpage); | |
364 | if (PageMappedToDisk(page)) | |
365 | SetPageMappedToDisk(newpage); | |
366 | ||
367 | if (PageDirty(page)) { | |
368 | clear_page_dirty_for_io(page); | |
3a902c5f NP |
369 | /* |
370 | * Want to mark the page and the radix tree as dirty, and | |
371 | * redo the accounting that clear_page_dirty_for_io undid, | |
372 | * but we can't use set_page_dirty because that function | |
373 | * is actually a signal that all of the page has become dirty. | |
374 | * Wheras only part of our page may be dirty. | |
375 | */ | |
376 | __set_page_dirty_nobuffers(newpage); | |
b20a3503 CL |
377 | } |
378 | ||
b291f000 | 379 | mlock_migrate_page(newpage, page); |
e9995ef9 | 380 | ksm_migrate_page(newpage, page); |
b291f000 | 381 | |
b20a3503 | 382 | ClearPageSwapCache(page); |
b20a3503 CL |
383 | ClearPagePrivate(page); |
384 | set_page_private(page, 0); | |
385 | page->mapping = NULL; | |
386 | ||
387 | /* | |
388 | * If any waiters have accumulated on the new page then | |
389 | * wake them up. | |
390 | */ | |
391 | if (PageWriteback(newpage)) | |
392 | end_page_writeback(newpage); | |
393 | } | |
b20a3503 | 394 | |
1d8b85cc CL |
395 | /************************************************************ |
396 | * Migration functions | |
397 | ***********************************************************/ | |
398 | ||
399 | /* Always fail migration. Used for mappings that are not movable */ | |
2d1db3b1 CL |
400 | int fail_migrate_page(struct address_space *mapping, |
401 | struct page *newpage, struct page *page) | |
1d8b85cc CL |
402 | { |
403 | return -EIO; | |
404 | } | |
405 | EXPORT_SYMBOL(fail_migrate_page); | |
406 | ||
b20a3503 CL |
407 | /* |
408 | * Common logic to directly migrate a single page suitable for | |
266cf658 | 409 | * pages that do not use PagePrivate/PagePrivate2. |
b20a3503 CL |
410 | * |
411 | * Pages are locked upon entry and exit. | |
412 | */ | |
2d1db3b1 CL |
413 | int migrate_page(struct address_space *mapping, |
414 | struct page *newpage, struct page *page) | |
b20a3503 CL |
415 | { |
416 | int rc; | |
417 | ||
418 | BUG_ON(PageWriteback(page)); /* Writeback must be complete */ | |
419 | ||
2d1db3b1 | 420 | rc = migrate_page_move_mapping(mapping, newpage, page); |
b20a3503 CL |
421 | |
422 | if (rc) | |
423 | return rc; | |
424 | ||
425 | migrate_page_copy(newpage, page); | |
b20a3503 CL |
426 | return 0; |
427 | } | |
428 | EXPORT_SYMBOL(migrate_page); | |
429 | ||
9361401e | 430 | #ifdef CONFIG_BLOCK |
1d8b85cc CL |
431 | /* |
432 | * Migration function for pages with buffers. This function can only be used | |
433 | * if the underlying filesystem guarantees that no other references to "page" | |
434 | * exist. | |
435 | */ | |
2d1db3b1 CL |
436 | int buffer_migrate_page(struct address_space *mapping, |
437 | struct page *newpage, struct page *page) | |
1d8b85cc | 438 | { |
1d8b85cc CL |
439 | struct buffer_head *bh, *head; |
440 | int rc; | |
441 | ||
1d8b85cc | 442 | if (!page_has_buffers(page)) |
2d1db3b1 | 443 | return migrate_page(mapping, newpage, page); |
1d8b85cc CL |
444 | |
445 | head = page_buffers(page); | |
446 | ||
2d1db3b1 | 447 | rc = migrate_page_move_mapping(mapping, newpage, page); |
1d8b85cc CL |
448 | |
449 | if (rc) | |
450 | return rc; | |
451 | ||
452 | bh = head; | |
453 | do { | |
454 | get_bh(bh); | |
455 | lock_buffer(bh); | |
456 | bh = bh->b_this_page; | |
457 | ||
458 | } while (bh != head); | |
459 | ||
460 | ClearPagePrivate(page); | |
461 | set_page_private(newpage, page_private(page)); | |
462 | set_page_private(page, 0); | |
463 | put_page(page); | |
464 | get_page(newpage); | |
465 | ||
466 | bh = head; | |
467 | do { | |
468 | set_bh_page(bh, newpage, bh_offset(bh)); | |
469 | bh = bh->b_this_page; | |
470 | ||
471 | } while (bh != head); | |
472 | ||
473 | SetPagePrivate(newpage); | |
474 | ||
475 | migrate_page_copy(newpage, page); | |
476 | ||
477 | bh = head; | |
478 | do { | |
479 | unlock_buffer(bh); | |
480 | put_bh(bh); | |
481 | bh = bh->b_this_page; | |
482 | ||
483 | } while (bh != head); | |
484 | ||
485 | return 0; | |
486 | } | |
487 | EXPORT_SYMBOL(buffer_migrate_page); | |
9361401e | 488 | #endif |
1d8b85cc | 489 | |
04e62a29 CL |
490 | /* |
491 | * Writeback a page to clean the dirty state | |
492 | */ | |
493 | static int writeout(struct address_space *mapping, struct page *page) | |
8351a6e4 | 494 | { |
04e62a29 CL |
495 | struct writeback_control wbc = { |
496 | .sync_mode = WB_SYNC_NONE, | |
497 | .nr_to_write = 1, | |
498 | .range_start = 0, | |
499 | .range_end = LLONG_MAX, | |
04e62a29 CL |
500 | .for_reclaim = 1 |
501 | }; | |
502 | int rc; | |
503 | ||
504 | if (!mapping->a_ops->writepage) | |
505 | /* No write method for the address space */ | |
506 | return -EINVAL; | |
507 | ||
508 | if (!clear_page_dirty_for_io(page)) | |
509 | /* Someone else already triggered a write */ | |
510 | return -EAGAIN; | |
511 | ||
8351a6e4 | 512 | /* |
04e62a29 CL |
513 | * A dirty page may imply that the underlying filesystem has |
514 | * the page on some queue. So the page must be clean for | |
515 | * migration. Writeout may mean we loose the lock and the | |
516 | * page state is no longer what we checked for earlier. | |
517 | * At this point we know that the migration attempt cannot | |
518 | * be successful. | |
8351a6e4 | 519 | */ |
04e62a29 | 520 | remove_migration_ptes(page, page); |
8351a6e4 | 521 | |
04e62a29 | 522 | rc = mapping->a_ops->writepage(page, &wbc); |
8351a6e4 | 523 | |
04e62a29 CL |
524 | if (rc != AOP_WRITEPAGE_ACTIVATE) |
525 | /* unlocked. Relock */ | |
526 | lock_page(page); | |
527 | ||
bda8550d | 528 | return (rc < 0) ? -EIO : -EAGAIN; |
04e62a29 CL |
529 | } |
530 | ||
531 | /* | |
532 | * Default handling if a filesystem does not provide a migration function. | |
533 | */ | |
534 | static int fallback_migrate_page(struct address_space *mapping, | |
535 | struct page *newpage, struct page *page) | |
536 | { | |
537 | if (PageDirty(page)) | |
538 | return writeout(mapping, page); | |
8351a6e4 CL |
539 | |
540 | /* | |
541 | * Buffers may be managed in a filesystem specific way. | |
542 | * We must have no buffers or drop them. | |
543 | */ | |
266cf658 | 544 | if (page_has_private(page) && |
8351a6e4 CL |
545 | !try_to_release_page(page, GFP_KERNEL)) |
546 | return -EAGAIN; | |
547 | ||
548 | return migrate_page(mapping, newpage, page); | |
549 | } | |
550 | ||
e24f0b8f CL |
551 | /* |
552 | * Move a page to a newly allocated page | |
553 | * The page is locked and all ptes have been successfully removed. | |
554 | * | |
555 | * The new page will have replaced the old page if this function | |
556 | * is successful. | |
894bc310 LS |
557 | * |
558 | * Return value: | |
559 | * < 0 - error code | |
560 | * == 0 - success | |
e24f0b8f | 561 | */ |
3fe2011f MG |
562 | static int move_to_new_page(struct page *newpage, struct page *page, |
563 | int remap_swapcache) | |
e24f0b8f CL |
564 | { |
565 | struct address_space *mapping; | |
566 | int rc; | |
567 | ||
568 | /* | |
569 | * Block others from accessing the page when we get around to | |
570 | * establishing additional references. We are the only one | |
571 | * holding a reference to the new page at this point. | |
572 | */ | |
529ae9aa | 573 | if (!trylock_page(newpage)) |
e24f0b8f CL |
574 | BUG(); |
575 | ||
576 | /* Prepare mapping for the new page.*/ | |
577 | newpage->index = page->index; | |
578 | newpage->mapping = page->mapping; | |
b2e18538 RR |
579 | if (PageSwapBacked(page)) |
580 | SetPageSwapBacked(newpage); | |
e24f0b8f CL |
581 | |
582 | mapping = page_mapping(page); | |
583 | if (!mapping) | |
584 | rc = migrate_page(mapping, newpage, page); | |
585 | else if (mapping->a_ops->migratepage) | |
586 | /* | |
587 | * Most pages have a mapping and most filesystems | |
588 | * should provide a migration function. Anonymous | |
589 | * pages are part of swap space which also has its | |
590 | * own migration function. This is the most common | |
591 | * path for page migration. | |
592 | */ | |
593 | rc = mapping->a_ops->migratepage(mapping, | |
594 | newpage, page); | |
595 | else | |
596 | rc = fallback_migrate_page(mapping, newpage, page); | |
597 | ||
3fe2011f | 598 | if (rc) { |
e24f0b8f | 599 | newpage->mapping = NULL; |
3fe2011f MG |
600 | } else { |
601 | if (remap_swapcache) | |
602 | remove_migration_ptes(page, newpage); | |
603 | } | |
e24f0b8f CL |
604 | |
605 | unlock_page(newpage); | |
606 | ||
607 | return rc; | |
608 | } | |
609 | ||
610 | /* | |
611 | * Obtain the lock on page, remove all ptes and migrate the page | |
612 | * to the newly allocated page in newpage. | |
613 | */ | |
95a402c3 | 614 | static int unmap_and_move(new_page_t get_new_page, unsigned long private, |
62b61f61 | 615 | struct page *page, int force, int offlining) |
e24f0b8f CL |
616 | { |
617 | int rc = 0; | |
742755a1 CL |
618 | int *result = NULL; |
619 | struct page *newpage = get_new_page(page, private, &result); | |
3fe2011f | 620 | int remap_swapcache = 1; |
989f89c5 | 621 | int rcu_locked = 0; |
ae41be37 | 622 | int charge = 0; |
e00e4316 | 623 | struct mem_cgroup *mem = NULL; |
3f6c8272 | 624 | struct anon_vma *anon_vma = NULL; |
95a402c3 CL |
625 | |
626 | if (!newpage) | |
627 | return -ENOMEM; | |
e24f0b8f | 628 | |
894bc310 | 629 | if (page_count(page) == 1) { |
e24f0b8f | 630 | /* page was freed from under us. So we are done. */ |
95a402c3 | 631 | goto move_newpage; |
894bc310 | 632 | } |
e24f0b8f | 633 | |
e8589cc1 | 634 | /* prepare cgroup just returns 0 or -ENOMEM */ |
e24f0b8f | 635 | rc = -EAGAIN; |
01b1ae63 | 636 | |
529ae9aa | 637 | if (!trylock_page(page)) { |
e24f0b8f | 638 | if (!force) |
95a402c3 | 639 | goto move_newpage; |
e24f0b8f CL |
640 | lock_page(page); |
641 | } | |
642 | ||
62b61f61 HD |
643 | /* |
644 | * Only memory hotplug's offline_pages() caller has locked out KSM, | |
645 | * and can safely migrate a KSM page. The other cases have skipped | |
646 | * PageKsm along with PageReserved - but it is only now when we have | |
647 | * the page lock that we can be certain it will not go KSM beneath us | |
648 | * (KSM will not upgrade a page from PageAnon to PageKsm when it sees | |
649 | * its pagecount raised, but only here do we take the page lock which | |
650 | * serializes that). | |
651 | */ | |
652 | if (PageKsm(page) && !offlining) { | |
653 | rc = -EBUSY; | |
654 | goto unlock; | |
655 | } | |
656 | ||
01b1ae63 | 657 | /* charge against new page */ |
ac39cf8c | 658 | charge = mem_cgroup_prepare_migration(page, newpage, &mem); |
01b1ae63 KH |
659 | if (charge == -ENOMEM) { |
660 | rc = -ENOMEM; | |
661 | goto unlock; | |
662 | } | |
663 | BUG_ON(charge); | |
664 | ||
e24f0b8f CL |
665 | if (PageWriteback(page)) { |
666 | if (!force) | |
01b1ae63 | 667 | goto uncharge; |
e24f0b8f CL |
668 | wait_on_page_writeback(page); |
669 | } | |
e24f0b8f | 670 | /* |
dc386d4d KH |
671 | * By try_to_unmap(), page->mapcount goes down to 0 here. In this case, |
672 | * we cannot notice that anon_vma is freed while we migrates a page. | |
673 | * This rcu_read_lock() delays freeing anon_vma pointer until the end | |
674 | * of migration. File cache pages are no problem because of page_lock() | |
989f89c5 KH |
675 | * File Caches may use write_page() or lock_page() in migration, then, |
676 | * just care Anon page here. | |
dc386d4d | 677 | */ |
989f89c5 KH |
678 | if (PageAnon(page)) { |
679 | rcu_read_lock(); | |
680 | rcu_locked = 1; | |
67b9509b | 681 | |
3fe2011f MG |
682 | /* Determine how to safely use anon_vma */ |
683 | if (!page_mapped(page)) { | |
684 | if (!PageSwapCache(page)) | |
685 | goto rcu_unlock; | |
67b9509b | 686 | |
3fe2011f MG |
687 | /* |
688 | * We cannot be sure that the anon_vma of an unmapped | |
689 | * swapcache page is safe to use because we don't | |
690 | * know in advance if the VMA that this page belonged | |
691 | * to still exists. If the VMA and others sharing the | |
692 | * data have been freed, then the anon_vma could | |
693 | * already be invalid. | |
694 | * | |
695 | * To avoid this possibility, swapcache pages get | |
696 | * migrated but are not remapped when migration | |
697 | * completes | |
698 | */ | |
699 | remap_swapcache = 0; | |
700 | } else { | |
701 | /* | |
702 | * Take a reference count on the anon_vma if the | |
703 | * page is mapped so that it is guaranteed to | |
704 | * exist when the page is remapped later | |
705 | */ | |
706 | anon_vma = page_anon_vma(page); | |
76545066 | 707 | get_anon_vma(anon_vma); |
3fe2011f | 708 | } |
989f89c5 | 709 | } |
62e1c553 | 710 | |
dc386d4d | 711 | /* |
62e1c553 SL |
712 | * Corner case handling: |
713 | * 1. When a new swap-cache page is read into, it is added to the LRU | |
714 | * and treated as swapcache but it has no rmap yet. | |
715 | * Calling try_to_unmap() against a page->mapping==NULL page will | |
716 | * trigger a BUG. So handle it here. | |
717 | * 2. An orphaned page (see truncate_complete_page) might have | |
718 | * fs-private metadata. The page can be picked up due to memory | |
719 | * offlining. Everywhere else except page reclaim, the page is | |
720 | * invisible to the vm, so the page can not be migrated. So try to | |
721 | * free the metadata, so the page can be freed. | |
e24f0b8f | 722 | */ |
62e1c553 | 723 | if (!page->mapping) { |
266cf658 | 724 | if (!PageAnon(page) && page_has_private(page)) { |
62e1c553 SL |
725 | /* |
726 | * Go direct to try_to_free_buffers() here because | |
727 | * a) that's what try_to_release_page() would do anyway | |
728 | * b) we may be under rcu_read_lock() here, so we can't | |
729 | * use GFP_KERNEL which is what try_to_release_page() | |
730 | * needs to be effective. | |
731 | */ | |
732 | try_to_free_buffers(page); | |
abfc3488 | 733 | goto rcu_unlock; |
62e1c553 | 734 | } |
abfc3488 | 735 | goto skip_unmap; |
62e1c553 SL |
736 | } |
737 | ||
dc386d4d | 738 | /* Establish migration ptes or remove ptes */ |
14fa31b8 | 739 | try_to_unmap(page, TTU_MIGRATION|TTU_IGNORE_MLOCK|TTU_IGNORE_ACCESS); |
dc386d4d | 740 | |
abfc3488 | 741 | skip_unmap: |
e6a1530d | 742 | if (!page_mapped(page)) |
3fe2011f | 743 | rc = move_to_new_page(newpage, page, remap_swapcache); |
e24f0b8f | 744 | |
3fe2011f | 745 | if (rc && remap_swapcache) |
e24f0b8f | 746 | remove_migration_ptes(page, page); |
dc386d4d | 747 | rcu_unlock: |
3f6c8272 MG |
748 | |
749 | /* Drop an anon_vma reference if we took one */ | |
76545066 RR |
750 | if (anon_vma) |
751 | drop_anon_vma(anon_vma); | |
3f6c8272 | 752 | |
989f89c5 KH |
753 | if (rcu_locked) |
754 | rcu_read_unlock(); | |
01b1ae63 KH |
755 | uncharge: |
756 | if (!charge) | |
757 | mem_cgroup_end_migration(mem, page, newpage); | |
e24f0b8f CL |
758 | unlock: |
759 | unlock_page(page); | |
95a402c3 | 760 | |
e24f0b8f | 761 | if (rc != -EAGAIN) { |
aaa994b3 CL |
762 | /* |
763 | * A page that has been migrated has all references | |
764 | * removed and will be freed. A page that has not been | |
765 | * migrated will have kepts its references and be | |
766 | * restored. | |
767 | */ | |
768 | list_del(&page->lru); | |
a731286d | 769 | dec_zone_page_state(page, NR_ISOLATED_ANON + |
6c0b1351 | 770 | page_is_file_cache(page)); |
894bc310 | 771 | putback_lru_page(page); |
e24f0b8f | 772 | } |
95a402c3 CL |
773 | |
774 | move_newpage: | |
894bc310 | 775 | |
95a402c3 CL |
776 | /* |
777 | * Move the new page to the LRU. If migration was not successful | |
778 | * then this will free the page. | |
779 | */ | |
894bc310 LS |
780 | putback_lru_page(newpage); |
781 | ||
742755a1 CL |
782 | if (result) { |
783 | if (rc) | |
784 | *result = rc; | |
785 | else | |
786 | *result = page_to_nid(newpage); | |
787 | } | |
e24f0b8f CL |
788 | return rc; |
789 | } | |
790 | ||
290408d4 NH |
791 | /* |
792 | * Counterpart of unmap_and_move_page() for hugepage migration. | |
793 | * | |
794 | * This function doesn't wait the completion of hugepage I/O | |
795 | * because there is no race between I/O and migration for hugepage. | |
796 | * Note that currently hugepage I/O occurs only in direct I/O | |
797 | * where no lock is held and PG_writeback is irrelevant, | |
798 | * and writeback status of all subpages are counted in the reference | |
799 | * count of the head page (i.e. if all subpages of a 2MB hugepage are | |
800 | * under direct I/O, the reference of the head page is 512 and a bit more.) | |
801 | * This means that when we try to migrate hugepage whose subpages are | |
802 | * doing direct I/O, some references remain after try_to_unmap() and | |
803 | * hugepage migration fails without data corruption. | |
804 | * | |
805 | * There is also no race when direct I/O is issued on the page under migration, | |
806 | * because then pte is replaced with migration swap entry and direct I/O code | |
807 | * will wait in the page fault for migration to complete. | |
808 | */ | |
809 | static int unmap_and_move_huge_page(new_page_t get_new_page, | |
810 | unsigned long private, struct page *hpage, | |
811 | int force, int offlining) | |
812 | { | |
813 | int rc = 0; | |
814 | int *result = NULL; | |
815 | struct page *new_hpage = get_new_page(hpage, private, &result); | |
816 | int rcu_locked = 0; | |
817 | struct anon_vma *anon_vma = NULL; | |
818 | ||
819 | if (!new_hpage) | |
820 | return -ENOMEM; | |
821 | ||
822 | rc = -EAGAIN; | |
823 | ||
824 | if (!trylock_page(hpage)) { | |
825 | if (!force) | |
826 | goto out; | |
827 | lock_page(hpage); | |
828 | } | |
829 | ||
830 | if (PageAnon(hpage)) { | |
831 | rcu_read_lock(); | |
832 | rcu_locked = 1; | |
833 | ||
834 | if (page_mapped(hpage)) { | |
835 | anon_vma = page_anon_vma(hpage); | |
836 | atomic_inc(&anon_vma->external_refcount); | |
837 | } | |
838 | } | |
839 | ||
840 | try_to_unmap(hpage, TTU_MIGRATION|TTU_IGNORE_MLOCK|TTU_IGNORE_ACCESS); | |
841 | ||
842 | if (!page_mapped(hpage)) | |
843 | rc = move_to_new_page(new_hpage, hpage, 1); | |
844 | ||
845 | if (rc) | |
846 | remove_migration_ptes(hpage, hpage); | |
847 | ||
848 | if (anon_vma && atomic_dec_and_lock(&anon_vma->external_refcount, | |
849 | &anon_vma->lock)) { | |
850 | int empty = list_empty(&anon_vma->head); | |
851 | spin_unlock(&anon_vma->lock); | |
852 | if (empty) | |
853 | anon_vma_free(anon_vma); | |
854 | } | |
855 | ||
856 | if (rcu_locked) | |
857 | rcu_read_unlock(); | |
858 | out: | |
859 | unlock_page(hpage); | |
860 | ||
861 | if (rc != -EAGAIN) { | |
862 | list_del(&hpage->lru); | |
863 | put_page(hpage); | |
864 | } | |
865 | ||
866 | put_page(new_hpage); | |
867 | ||
868 | if (result) { | |
869 | if (rc) | |
870 | *result = rc; | |
871 | else | |
872 | *result = page_to_nid(new_hpage); | |
873 | } | |
874 | return rc; | |
875 | } | |
876 | ||
b20a3503 CL |
877 | /* |
878 | * migrate_pages | |
879 | * | |
95a402c3 CL |
880 | * The function takes one list of pages to migrate and a function |
881 | * that determines from the page to be migrated and the private data | |
882 | * the target of the move and allocates the page. | |
b20a3503 CL |
883 | * |
884 | * The function returns after 10 attempts or if no pages | |
885 | * are movable anymore because to has become empty | |
aaa994b3 | 886 | * or no retryable pages exist anymore. All pages will be |
e9534b3f | 887 | * returned to the LRU or freed. |
b20a3503 | 888 | * |
95a402c3 | 889 | * Return: Number of pages not migrated or error code. |
b20a3503 | 890 | */ |
95a402c3 | 891 | int migrate_pages(struct list_head *from, |
62b61f61 | 892 | new_page_t get_new_page, unsigned long private, int offlining) |
b20a3503 | 893 | { |
e24f0b8f | 894 | int retry = 1; |
b20a3503 CL |
895 | int nr_failed = 0; |
896 | int pass = 0; | |
897 | struct page *page; | |
898 | struct page *page2; | |
899 | int swapwrite = current->flags & PF_SWAPWRITE; | |
900 | int rc; | |
901 | ||
902 | if (!swapwrite) | |
903 | current->flags |= PF_SWAPWRITE; | |
904 | ||
e24f0b8f CL |
905 | for(pass = 0; pass < 10 && retry; pass++) { |
906 | retry = 0; | |
b20a3503 | 907 | |
e24f0b8f | 908 | list_for_each_entry_safe(page, page2, from, lru) { |
e24f0b8f | 909 | cond_resched(); |
2d1db3b1 | 910 | |
95a402c3 | 911 | rc = unmap_and_move(get_new_page, private, |
62b61f61 | 912 | page, pass > 2, offlining); |
2d1db3b1 | 913 | |
e24f0b8f | 914 | switch(rc) { |
95a402c3 CL |
915 | case -ENOMEM: |
916 | goto out; | |
e24f0b8f | 917 | case -EAGAIN: |
2d1db3b1 | 918 | retry++; |
e24f0b8f CL |
919 | break; |
920 | case 0: | |
e24f0b8f CL |
921 | break; |
922 | default: | |
2d1db3b1 | 923 | /* Permanent failure */ |
2d1db3b1 | 924 | nr_failed++; |
e24f0b8f | 925 | break; |
2d1db3b1 | 926 | } |
b20a3503 CL |
927 | } |
928 | } | |
95a402c3 CL |
929 | rc = 0; |
930 | out: | |
b20a3503 CL |
931 | if (!swapwrite) |
932 | current->flags &= ~PF_SWAPWRITE; | |
933 | ||
aaa994b3 | 934 | putback_lru_pages(from); |
b20a3503 | 935 | |
95a402c3 CL |
936 | if (rc) |
937 | return rc; | |
b20a3503 | 938 | |
95a402c3 | 939 | return nr_failed + retry; |
b20a3503 | 940 | } |
95a402c3 | 941 | |
290408d4 NH |
942 | int migrate_huge_pages(struct list_head *from, |
943 | new_page_t get_new_page, unsigned long private, int offlining) | |
944 | { | |
945 | int retry = 1; | |
946 | int nr_failed = 0; | |
947 | int pass = 0; | |
948 | struct page *page; | |
949 | struct page *page2; | |
950 | int rc; | |
951 | ||
952 | for (pass = 0; pass < 10 && retry; pass++) { | |
953 | retry = 0; | |
954 | ||
955 | list_for_each_entry_safe(page, page2, from, lru) { | |
956 | cond_resched(); | |
957 | ||
958 | rc = unmap_and_move_huge_page(get_new_page, | |
959 | private, page, pass > 2, offlining); | |
960 | ||
961 | switch(rc) { | |
962 | case -ENOMEM: | |
963 | goto out; | |
964 | case -EAGAIN: | |
965 | retry++; | |
966 | break; | |
967 | case 0: | |
968 | break; | |
969 | default: | |
970 | /* Permanent failure */ | |
971 | nr_failed++; | |
972 | break; | |
973 | } | |
974 | } | |
975 | } | |
976 | rc = 0; | |
977 | out: | |
978 | ||
979 | list_for_each_entry_safe(page, page2, from, lru) | |
980 | put_page(page); | |
981 | ||
982 | if (rc) | |
983 | return rc; | |
984 | ||
985 | return nr_failed + retry; | |
986 | } | |
987 | ||
742755a1 CL |
988 | #ifdef CONFIG_NUMA |
989 | /* | |
990 | * Move a list of individual pages | |
991 | */ | |
992 | struct page_to_node { | |
993 | unsigned long addr; | |
994 | struct page *page; | |
995 | int node; | |
996 | int status; | |
997 | }; | |
998 | ||
999 | static struct page *new_page_node(struct page *p, unsigned long private, | |
1000 | int **result) | |
1001 | { | |
1002 | struct page_to_node *pm = (struct page_to_node *)private; | |
1003 | ||
1004 | while (pm->node != MAX_NUMNODES && pm->page != p) | |
1005 | pm++; | |
1006 | ||
1007 | if (pm->node == MAX_NUMNODES) | |
1008 | return NULL; | |
1009 | ||
1010 | *result = &pm->status; | |
1011 | ||
6484eb3e | 1012 | return alloc_pages_exact_node(pm->node, |
769848c0 | 1013 | GFP_HIGHUSER_MOVABLE | GFP_THISNODE, 0); |
742755a1 CL |
1014 | } |
1015 | ||
1016 | /* | |
1017 | * Move a set of pages as indicated in the pm array. The addr | |
1018 | * field must be set to the virtual address of the page to be moved | |
1019 | * and the node number must contain a valid target node. | |
5e9a0f02 | 1020 | * The pm array ends with node = MAX_NUMNODES. |
742755a1 | 1021 | */ |
5e9a0f02 BG |
1022 | static int do_move_page_to_node_array(struct mm_struct *mm, |
1023 | struct page_to_node *pm, | |
1024 | int migrate_all) | |
742755a1 CL |
1025 | { |
1026 | int err; | |
1027 | struct page_to_node *pp; | |
1028 | LIST_HEAD(pagelist); | |
1029 | ||
1030 | down_read(&mm->mmap_sem); | |
1031 | ||
1032 | /* | |
1033 | * Build a list of pages to migrate | |
1034 | */ | |
742755a1 CL |
1035 | for (pp = pm; pp->node != MAX_NUMNODES; pp++) { |
1036 | struct vm_area_struct *vma; | |
1037 | struct page *page; | |
1038 | ||
742755a1 CL |
1039 | err = -EFAULT; |
1040 | vma = find_vma(mm, pp->addr); | |
0dc952dc | 1041 | if (!vma || !vma_migratable(vma)) |
742755a1 CL |
1042 | goto set_status; |
1043 | ||
1044 | page = follow_page(vma, pp->addr, FOLL_GET); | |
89f5b7da LT |
1045 | |
1046 | err = PTR_ERR(page); | |
1047 | if (IS_ERR(page)) | |
1048 | goto set_status; | |
1049 | ||
742755a1 CL |
1050 | err = -ENOENT; |
1051 | if (!page) | |
1052 | goto set_status; | |
1053 | ||
62b61f61 HD |
1054 | /* Use PageReserved to check for zero page */ |
1055 | if (PageReserved(page) || PageKsm(page)) | |
742755a1 CL |
1056 | goto put_and_set; |
1057 | ||
1058 | pp->page = page; | |
1059 | err = page_to_nid(page); | |
1060 | ||
1061 | if (err == pp->node) | |
1062 | /* | |
1063 | * Node already in the right place | |
1064 | */ | |
1065 | goto put_and_set; | |
1066 | ||
1067 | err = -EACCES; | |
1068 | if (page_mapcount(page) > 1 && | |
1069 | !migrate_all) | |
1070 | goto put_and_set; | |
1071 | ||
62695a84 | 1072 | err = isolate_lru_page(page); |
6d9c285a | 1073 | if (!err) { |
62695a84 | 1074 | list_add_tail(&page->lru, &pagelist); |
6d9c285a KM |
1075 | inc_zone_page_state(page, NR_ISOLATED_ANON + |
1076 | page_is_file_cache(page)); | |
1077 | } | |
742755a1 CL |
1078 | put_and_set: |
1079 | /* | |
1080 | * Either remove the duplicate refcount from | |
1081 | * isolate_lru_page() or drop the page ref if it was | |
1082 | * not isolated. | |
1083 | */ | |
1084 | put_page(page); | |
1085 | set_status: | |
1086 | pp->status = err; | |
1087 | } | |
1088 | ||
e78bbfa8 | 1089 | err = 0; |
742755a1 CL |
1090 | if (!list_empty(&pagelist)) |
1091 | err = migrate_pages(&pagelist, new_page_node, | |
62b61f61 | 1092 | (unsigned long)pm, 0); |
742755a1 CL |
1093 | |
1094 | up_read(&mm->mmap_sem); | |
1095 | return err; | |
1096 | } | |
1097 | ||
5e9a0f02 BG |
1098 | /* |
1099 | * Migrate an array of page address onto an array of nodes and fill | |
1100 | * the corresponding array of status. | |
1101 | */ | |
1102 | static int do_pages_move(struct mm_struct *mm, struct task_struct *task, | |
1103 | unsigned long nr_pages, | |
1104 | const void __user * __user *pages, | |
1105 | const int __user *nodes, | |
1106 | int __user *status, int flags) | |
1107 | { | |
3140a227 | 1108 | struct page_to_node *pm; |
5e9a0f02 | 1109 | nodemask_t task_nodes; |
3140a227 BG |
1110 | unsigned long chunk_nr_pages; |
1111 | unsigned long chunk_start; | |
1112 | int err; | |
5e9a0f02 BG |
1113 | |
1114 | task_nodes = cpuset_mems_allowed(task); | |
1115 | ||
3140a227 BG |
1116 | err = -ENOMEM; |
1117 | pm = (struct page_to_node *)__get_free_page(GFP_KERNEL); | |
1118 | if (!pm) | |
5e9a0f02 | 1119 | goto out; |
35282a2d BG |
1120 | |
1121 | migrate_prep(); | |
1122 | ||
5e9a0f02 | 1123 | /* |
3140a227 BG |
1124 | * Store a chunk of page_to_node array in a page, |
1125 | * but keep the last one as a marker | |
5e9a0f02 | 1126 | */ |
3140a227 | 1127 | chunk_nr_pages = (PAGE_SIZE / sizeof(struct page_to_node)) - 1; |
5e9a0f02 | 1128 | |
3140a227 BG |
1129 | for (chunk_start = 0; |
1130 | chunk_start < nr_pages; | |
1131 | chunk_start += chunk_nr_pages) { | |
1132 | int j; | |
5e9a0f02 | 1133 | |
3140a227 BG |
1134 | if (chunk_start + chunk_nr_pages > nr_pages) |
1135 | chunk_nr_pages = nr_pages - chunk_start; | |
1136 | ||
1137 | /* fill the chunk pm with addrs and nodes from user-space */ | |
1138 | for (j = 0; j < chunk_nr_pages; j++) { | |
1139 | const void __user *p; | |
5e9a0f02 BG |
1140 | int node; |
1141 | ||
3140a227 BG |
1142 | err = -EFAULT; |
1143 | if (get_user(p, pages + j + chunk_start)) | |
1144 | goto out_pm; | |
1145 | pm[j].addr = (unsigned long) p; | |
1146 | ||
1147 | if (get_user(node, nodes + j + chunk_start)) | |
5e9a0f02 BG |
1148 | goto out_pm; |
1149 | ||
1150 | err = -ENODEV; | |
6f5a55f1 LT |
1151 | if (node < 0 || node >= MAX_NUMNODES) |
1152 | goto out_pm; | |
1153 | ||
5e9a0f02 BG |
1154 | if (!node_state(node, N_HIGH_MEMORY)) |
1155 | goto out_pm; | |
1156 | ||
1157 | err = -EACCES; | |
1158 | if (!node_isset(node, task_nodes)) | |
1159 | goto out_pm; | |
1160 | ||
3140a227 BG |
1161 | pm[j].node = node; |
1162 | } | |
1163 | ||
1164 | /* End marker for this chunk */ | |
1165 | pm[chunk_nr_pages].node = MAX_NUMNODES; | |
1166 | ||
1167 | /* Migrate this chunk */ | |
1168 | err = do_move_page_to_node_array(mm, pm, | |
1169 | flags & MPOL_MF_MOVE_ALL); | |
1170 | if (err < 0) | |
1171 | goto out_pm; | |
5e9a0f02 | 1172 | |
5e9a0f02 | 1173 | /* Return status information */ |
3140a227 BG |
1174 | for (j = 0; j < chunk_nr_pages; j++) |
1175 | if (put_user(pm[j].status, status + j + chunk_start)) { | |
5e9a0f02 | 1176 | err = -EFAULT; |
3140a227 BG |
1177 | goto out_pm; |
1178 | } | |
1179 | } | |
1180 | err = 0; | |
5e9a0f02 BG |
1181 | |
1182 | out_pm: | |
3140a227 | 1183 | free_page((unsigned long)pm); |
5e9a0f02 BG |
1184 | out: |
1185 | return err; | |
1186 | } | |
1187 | ||
742755a1 | 1188 | /* |
2f007e74 | 1189 | * Determine the nodes of an array of pages and store it in an array of status. |
742755a1 | 1190 | */ |
80bba129 BG |
1191 | static void do_pages_stat_array(struct mm_struct *mm, unsigned long nr_pages, |
1192 | const void __user **pages, int *status) | |
742755a1 | 1193 | { |
2f007e74 | 1194 | unsigned long i; |
2f007e74 | 1195 | |
742755a1 CL |
1196 | down_read(&mm->mmap_sem); |
1197 | ||
2f007e74 | 1198 | for (i = 0; i < nr_pages; i++) { |
80bba129 | 1199 | unsigned long addr = (unsigned long)(*pages); |
742755a1 CL |
1200 | struct vm_area_struct *vma; |
1201 | struct page *page; | |
c095adbc | 1202 | int err = -EFAULT; |
2f007e74 BG |
1203 | |
1204 | vma = find_vma(mm, addr); | |
742755a1 CL |
1205 | if (!vma) |
1206 | goto set_status; | |
1207 | ||
2f007e74 | 1208 | page = follow_page(vma, addr, 0); |
89f5b7da LT |
1209 | |
1210 | err = PTR_ERR(page); | |
1211 | if (IS_ERR(page)) | |
1212 | goto set_status; | |
1213 | ||
742755a1 CL |
1214 | err = -ENOENT; |
1215 | /* Use PageReserved to check for zero page */ | |
62b61f61 | 1216 | if (!page || PageReserved(page) || PageKsm(page)) |
742755a1 CL |
1217 | goto set_status; |
1218 | ||
1219 | err = page_to_nid(page); | |
1220 | set_status: | |
80bba129 BG |
1221 | *status = err; |
1222 | ||
1223 | pages++; | |
1224 | status++; | |
1225 | } | |
1226 | ||
1227 | up_read(&mm->mmap_sem); | |
1228 | } | |
1229 | ||
1230 | /* | |
1231 | * Determine the nodes of a user array of pages and store it in | |
1232 | * a user array of status. | |
1233 | */ | |
1234 | static int do_pages_stat(struct mm_struct *mm, unsigned long nr_pages, | |
1235 | const void __user * __user *pages, | |
1236 | int __user *status) | |
1237 | { | |
1238 | #define DO_PAGES_STAT_CHUNK_NR 16 | |
1239 | const void __user *chunk_pages[DO_PAGES_STAT_CHUNK_NR]; | |
1240 | int chunk_status[DO_PAGES_STAT_CHUNK_NR]; | |
80bba129 | 1241 | |
87b8d1ad PA |
1242 | while (nr_pages) { |
1243 | unsigned long chunk_nr; | |
80bba129 | 1244 | |
87b8d1ad PA |
1245 | chunk_nr = nr_pages; |
1246 | if (chunk_nr > DO_PAGES_STAT_CHUNK_NR) | |
1247 | chunk_nr = DO_PAGES_STAT_CHUNK_NR; | |
1248 | ||
1249 | if (copy_from_user(chunk_pages, pages, chunk_nr * sizeof(*chunk_pages))) | |
1250 | break; | |
80bba129 BG |
1251 | |
1252 | do_pages_stat_array(mm, chunk_nr, chunk_pages, chunk_status); | |
1253 | ||
87b8d1ad PA |
1254 | if (copy_to_user(status, chunk_status, chunk_nr * sizeof(*status))) |
1255 | break; | |
742755a1 | 1256 | |
87b8d1ad PA |
1257 | pages += chunk_nr; |
1258 | status += chunk_nr; | |
1259 | nr_pages -= chunk_nr; | |
1260 | } | |
1261 | return nr_pages ? -EFAULT : 0; | |
742755a1 CL |
1262 | } |
1263 | ||
1264 | /* | |
1265 | * Move a list of pages in the address space of the currently executing | |
1266 | * process. | |
1267 | */ | |
938bb9f5 HC |
1268 | SYSCALL_DEFINE6(move_pages, pid_t, pid, unsigned long, nr_pages, |
1269 | const void __user * __user *, pages, | |
1270 | const int __user *, nodes, | |
1271 | int __user *, status, int, flags) | |
742755a1 | 1272 | { |
c69e8d9c | 1273 | const struct cred *cred = current_cred(), *tcred; |
742755a1 | 1274 | struct task_struct *task; |
742755a1 | 1275 | struct mm_struct *mm; |
5e9a0f02 | 1276 | int err; |
742755a1 CL |
1277 | |
1278 | /* Check flags */ | |
1279 | if (flags & ~(MPOL_MF_MOVE|MPOL_MF_MOVE_ALL)) | |
1280 | return -EINVAL; | |
1281 | ||
1282 | if ((flags & MPOL_MF_MOVE_ALL) && !capable(CAP_SYS_NICE)) | |
1283 | return -EPERM; | |
1284 | ||
1285 | /* Find the mm_struct */ | |
1286 | read_lock(&tasklist_lock); | |
228ebcbe | 1287 | task = pid ? find_task_by_vpid(pid) : current; |
742755a1 CL |
1288 | if (!task) { |
1289 | read_unlock(&tasklist_lock); | |
1290 | return -ESRCH; | |
1291 | } | |
1292 | mm = get_task_mm(task); | |
1293 | read_unlock(&tasklist_lock); | |
1294 | ||
1295 | if (!mm) | |
1296 | return -EINVAL; | |
1297 | ||
1298 | /* | |
1299 | * Check if this process has the right to modify the specified | |
1300 | * process. The right exists if the process has administrative | |
1301 | * capabilities, superuser privileges or the same | |
1302 | * userid as the target process. | |
1303 | */ | |
c69e8d9c DH |
1304 | rcu_read_lock(); |
1305 | tcred = __task_cred(task); | |
b6dff3ec DH |
1306 | if (cred->euid != tcred->suid && cred->euid != tcred->uid && |
1307 | cred->uid != tcred->suid && cred->uid != tcred->uid && | |
742755a1 | 1308 | !capable(CAP_SYS_NICE)) { |
c69e8d9c | 1309 | rcu_read_unlock(); |
742755a1 | 1310 | err = -EPERM; |
5e9a0f02 | 1311 | goto out; |
742755a1 | 1312 | } |
c69e8d9c | 1313 | rcu_read_unlock(); |
742755a1 | 1314 | |
86c3a764 DQ |
1315 | err = security_task_movememory(task); |
1316 | if (err) | |
5e9a0f02 | 1317 | goto out; |
86c3a764 | 1318 | |
5e9a0f02 BG |
1319 | if (nodes) { |
1320 | err = do_pages_move(mm, task, nr_pages, pages, nodes, status, | |
1321 | flags); | |
1322 | } else { | |
2f007e74 | 1323 | err = do_pages_stat(mm, nr_pages, pages, status); |
742755a1 CL |
1324 | } |
1325 | ||
742755a1 | 1326 | out: |
742755a1 CL |
1327 | mmput(mm); |
1328 | return err; | |
1329 | } | |
742755a1 | 1330 | |
7b2259b3 CL |
1331 | /* |
1332 | * Call migration functions in the vma_ops that may prepare | |
1333 | * memory in a vm for migration. migration functions may perform | |
1334 | * the migration for vmas that do not have an underlying page struct. | |
1335 | */ | |
1336 | int migrate_vmas(struct mm_struct *mm, const nodemask_t *to, | |
1337 | const nodemask_t *from, unsigned long flags) | |
1338 | { | |
1339 | struct vm_area_struct *vma; | |
1340 | int err = 0; | |
1341 | ||
1001c9fb | 1342 | for (vma = mm->mmap; vma && !err; vma = vma->vm_next) { |
7b2259b3 CL |
1343 | if (vma->vm_ops && vma->vm_ops->migrate) { |
1344 | err = vma->vm_ops->migrate(vma, to, from, flags); | |
1345 | if (err) | |
1346 | break; | |
1347 | } | |
1348 | } | |
1349 | return err; | |
1350 | } | |
83d1674a | 1351 | #endif |