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15#include <linux/migrate.h>
16#include <linux/module.h>
17#include <linux/swap.h>
18#include <linux/swapops.h>
19#include <linux/pagemap.h>
20#include <linux/buffer_head.h>
21#include <linux/mm_inline.h>
22#include <linux/nsproxy.h>
23#include <linux/pagevec.h>
24#include <linux/rmap.h>
25#include <linux/topology.h>
26#include <linux/cpu.h>
27#include <linux/cpuset.h>
28#include <linux/writeback.h>
29#include <linux/mempolicy.h>
30#include <linux/vmalloc.h>
31#include <linux/security.h>
32
33#include "internal.h"
34
35#define lru_to_page(_head) (list_entry((_head)->prev, struct page, lru))
36
37
38
39
40
41
42
43
44
45int isolate_lru_page(struct page *page, struct list_head *pagelist)
46{
47 int ret = -EBUSY;
48
49 if (PageLRU(page)) {
50 struct zone *zone = page_zone(page);
51
52 spin_lock_irq(&zone->lru_lock);
53 if (PageLRU(page) && get_page_unless_zero(page)) {
54 ret = 0;
55 ClearPageLRU(page);
56 if (PageActive(page))
57 del_page_from_active_list(zone, page);
58 else
59 del_page_from_inactive_list(zone, page);
60 list_add_tail(&page->lru, pagelist);
61 }
62 spin_unlock_irq(&zone->lru_lock);
63 }
64 return ret;
65}
66
67
68
69
70
71int migrate_prep(void)
72{
73
74
75
76
77
78
79 lru_add_drain_all();
80
81 return 0;
82}
83
84static inline void move_to_lru(struct page *page)
85{
86 if (PageActive(page)) {
87
88
89
90
91 ClearPageActive(page);
92 lru_cache_add_active(page);
93 } else {
94 lru_cache_add(page);
95 }
96 put_page(page);
97}
98
99
100
101
102
103
104int putback_lru_pages(struct list_head *l)
105{
106 struct page *page;
107 struct page *page2;
108 int count = 0;
109
110 list_for_each_entry_safe(page, page2, l, lru) {
111 list_del(&page->lru);
112 move_to_lru(page);
113 count++;
114 }
115 return count;
116}
117
118static inline int is_swap_pte(pte_t pte)
119{
120 return !pte_none(pte) && !pte_present(pte) && !pte_file(pte);
121}
122
123
124
125
126static void remove_migration_pte(struct vm_area_struct *vma,
127 struct page *old, struct page *new)
128{
129 struct mm_struct *mm = vma->vm_mm;
130 swp_entry_t entry;
131 pgd_t *pgd;
132 pud_t *pud;
133 pmd_t *pmd;
134 pte_t *ptep, pte;
135 spinlock_t *ptl;
136 unsigned long addr = page_address_in_vma(new, vma);
137
138 if (addr == -EFAULT)
139 return;
140
141 pgd = pgd_offset(mm, addr);
142 if (!pgd_present(*pgd))
143 return;
144
145 pud = pud_offset(pgd, addr);
146 if (!pud_present(*pud))
147 return;
148
149 pmd = pmd_offset(pud, addr);
150 if (!pmd_present(*pmd))
151 return;
152
153 ptep = pte_offset_map(pmd, addr);
154
155 if (!is_swap_pte(*ptep)) {
156 pte_unmap(ptep);
157 return;
158 }
159
160 ptl = pte_lockptr(mm, pmd);
161 spin_lock(ptl);
162 pte = *ptep;
163 if (!is_swap_pte(pte))
164 goto out;
165
166 entry = pte_to_swp_entry(pte);
167
168 if (!is_migration_entry(entry) || migration_entry_to_page(entry) != old)
169 goto out;
170
171 get_page(new);
172 pte = pte_mkold(mk_pte(new, vma->vm_page_prot));
173 if (is_write_migration_entry(entry))
174 pte = pte_mkwrite(pte);
175 flush_cache_page(vma, addr, pte_pfn(pte));
176 set_pte_at(mm, addr, ptep, pte);
177
178 if (PageAnon(new))
179 page_add_anon_rmap(new, vma, addr);
180 else
181 page_add_file_rmap(new);
182
183
184 update_mmu_cache(vma, addr, pte);
185
186out:
187 pte_unmap_unlock(ptep, ptl);
188}
189
190
191
192
193
194static void remove_file_migration_ptes(struct page *old, struct page *new)
195{
196 struct vm_area_struct *vma;
197 struct address_space *mapping = page_mapping(new);
198 struct prio_tree_iter iter;
199 pgoff_t pgoff = new->index << (PAGE_CACHE_SHIFT - PAGE_SHIFT);
200
201 if (!mapping)
202 return;
203
204 spin_lock(&mapping->i_mmap_lock);
205
206 vma_prio_tree_foreach(vma, &iter, &mapping->i_mmap, pgoff, pgoff)
207 remove_migration_pte(vma, old, new);
208
209 spin_unlock(&mapping->i_mmap_lock);
210}
211
212
213
214
215
216static void remove_anon_migration_ptes(struct page *old, struct page *new)
217{
218 struct anon_vma *anon_vma;
219 struct vm_area_struct *vma;
220 unsigned long mapping;
221
222 mapping = (unsigned long)new->mapping;
223
224 if (!mapping || (mapping & PAGE_MAPPING_ANON) == 0)
225 return;
226
227
228
229
230 anon_vma = (struct anon_vma *) (mapping - PAGE_MAPPING_ANON);
231 spin_lock(&anon_vma->lock);
232
233 list_for_each_entry(vma, &anon_vma->head, anon_vma_node)
234 remove_migration_pte(vma, old, new);
235
236 spin_unlock(&anon_vma->lock);
237}
238
239
240
241
242
243static void remove_migration_ptes(struct page *old, struct page *new)
244{
245 if (PageAnon(new))
246 remove_anon_migration_ptes(old, new);
247 else
248 remove_file_migration_ptes(old, new);
249}
250
251
252
253
254
255
256
257
258void migration_entry_wait(struct mm_struct *mm, pmd_t *pmd,
259 unsigned long address)
260{
261 pte_t *ptep, pte;
262 spinlock_t *ptl;
263 swp_entry_t entry;
264 struct page *page;
265
266 ptep = pte_offset_map_lock(mm, pmd, address, &ptl);
267 pte = *ptep;
268 if (!is_swap_pte(pte))
269 goto out;
270
271 entry = pte_to_swp_entry(pte);
272 if (!is_migration_entry(entry))
273 goto out;
274
275 page = migration_entry_to_page(entry);
276
277 get_page(page);
278 pte_unmap_unlock(ptep, ptl);
279 wait_on_page_locked(page);
280 put_page(page);
281 return;
282out:
283 pte_unmap_unlock(ptep, ptl);
284}
285
286
287
288
289
290
291
292
293
294static int migrate_page_move_mapping(struct address_space *mapping,
295 struct page *newpage, struct page *page)
296{
297 void **pslot;
298
299 if (!mapping) {
300
301 if (page_count(page) != 1)
302 return -EAGAIN;
303 return 0;
304 }
305
306 write_lock_irq(&mapping->tree_lock);
307
308 pslot = radix_tree_lookup_slot(&mapping->page_tree,
309 page_index(page));
310
311 if (page_count(page) != 2 + !!PagePrivate(page) ||
312 (struct page *)radix_tree_deref_slot(pslot) != page) {
313 write_unlock_irq(&mapping->tree_lock);
314 return -EAGAIN;
315 }
316
317
318
319
320 get_page(newpage);
321#ifdef CONFIG_SWAP
322 if (PageSwapCache(page)) {
323 SetPageSwapCache(newpage);
324 set_page_private(newpage, page_private(page));
325 }
326#endif
327
328 radix_tree_replace_slot(pslot, newpage);
329
330
331
332
333
334 __put_page(page);
335
336
337
338
339
340
341
342
343
344
345
346 __dec_zone_page_state(page, NR_FILE_PAGES);
347 __inc_zone_page_state(newpage, NR_FILE_PAGES);
348
349 write_unlock_irq(&mapping->tree_lock);
350
351 return 0;
352}
353
354
355
356
357static void migrate_page_copy(struct page *newpage, struct page *page)
358{
359 copy_highpage(newpage, page);
360
361 if (PageError(page))
362 SetPageError(newpage);
363 if (PageReferenced(page))
364 SetPageReferenced(newpage);
365 if (PageUptodate(page))
366 SetPageUptodate(newpage);
367 if (PageActive(page))
368 SetPageActive(newpage);
369 if (PageChecked(page))
370 SetPageChecked(newpage);
371 if (PageMappedToDisk(page))
372 SetPageMappedToDisk(newpage);
373
374 if (PageDirty(page)) {
375 clear_page_dirty_for_io(page);
376 set_page_dirty(newpage);
377 }
378
379#ifdef CONFIG_SWAP
380 ClearPageSwapCache(page);
381#endif
382 ClearPageActive(page);
383 ClearPagePrivate(page);
384 set_page_private(page, 0);
385 page->mapping = NULL;
386
387
388
389
390
391 if (PageWriteback(newpage))
392 end_page_writeback(newpage);
393}
394
395
396
397
398
399
400int fail_migrate_page(struct address_space *mapping,
401 struct page *newpage, struct page *page)
402{
403 return -EIO;
404}
405EXPORT_SYMBOL(fail_migrate_page);
406
407
408
409
410
411
412
413int migrate_page(struct address_space *mapping,
414 struct page *newpage, struct page *page)
415{
416 int rc;
417
418 BUG_ON(PageWriteback(page));
419
420 rc = migrate_page_move_mapping(mapping, newpage, page);
421
422 if (rc)
423 return rc;
424
425 migrate_page_copy(newpage, page);
426 return 0;
427}
428EXPORT_SYMBOL(migrate_page);
429
430#ifdef CONFIG_BLOCK
431
432
433
434
435
436int buffer_migrate_page(struct address_space *mapping,
437 struct page *newpage, struct page *page)
438{
439 struct buffer_head *bh, *head;
440 int rc;
441
442 if (!page_has_buffers(page))
443 return migrate_page(mapping, newpage, page);
444
445 head = page_buffers(page);
446
447 rc = migrate_page_move_mapping(mapping, newpage, page);
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}
487EXPORT_SYMBOL(buffer_migrate_page);
488#endif
489
490
491
492
493static int writeout(struct address_space *mapping, struct page *page)
494{
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,
500 .nonblocking = 1,
501 .for_reclaim = 1
502 };
503 int rc;
504
505 if (!mapping->a_ops->writepage)
506
507 return -EINVAL;
508
509 if (!clear_page_dirty_for_io(page))
510
511 return -EAGAIN;
512
513
514
515
516
517
518
519
520
521 remove_migration_ptes(page, page);
522
523 rc = mapping->a_ops->writepage(page, &wbc);
524 if (rc < 0)
525
526 return -EIO;
527
528 if (rc != AOP_WRITEPAGE_ACTIVATE)
529
530 lock_page(page);
531
532 return -EAGAIN;
533}
534
535
536
537
538static 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);
543
544
545
546
547
548 if (PagePrivate(page) &&
549 !try_to_release_page(page, GFP_KERNEL))
550 return -EAGAIN;
551
552 return migrate_page(mapping, newpage, page);
553}
554
555
556
557
558
559
560
561
562static int move_to_new_page(struct page *newpage, struct page *page)
563{
564 struct address_space *mapping;
565 int rc;
566
567
568
569
570
571
572 if (TestSetPageLocked(newpage))
573 BUG();
574
575
576 newpage->index = page->index;
577 newpage->mapping = page->mapping;
578
579 mapping = page_mapping(page);
580 if (!mapping)
581 rc = migrate_page(mapping, newpage, page);
582 else if (mapping->a_ops->migratepage)
583
584
585
586
587
588
589
590 rc = mapping->a_ops->migratepage(mapping,
591 newpage, page);
592 else
593 rc = fallback_migrate_page(mapping, newpage, page);
594
595 if (!rc)
596 remove_migration_ptes(page, newpage);
597 else
598 newpage->mapping = NULL;
599
600 unlock_page(newpage);
601
602 return rc;
603}
604
605
606
607
608
609static int unmap_and_move(new_page_t get_new_page, unsigned long private,
610 struct page *page, int force)
611{
612 int rc = 0;
613 int *result = NULL;
614 struct page *newpage = get_new_page(page, private, &result);
615 int rcu_locked = 0;
616
617 if (!newpage)
618 return -ENOMEM;
619
620 if (page_count(page) == 1)
621
622 goto move_newpage;
623
624 rc = -EAGAIN;
625 if (TestSetPageLocked(page)) {
626 if (!force)
627 goto move_newpage;
628 lock_page(page);
629 }
630
631 if (PageWriteback(page)) {
632 if (!force)
633 goto unlock;
634 wait_on_page_writeback(page);
635 }
636
637
638
639
640
641
642
643
644 if (PageAnon(page)) {
645 rcu_read_lock();
646 rcu_locked = 1;
647 }
648
649
650
651
652
653
654
655 if (!page->mapping)
656 goto rcu_unlock;
657
658 try_to_unmap(page, 1);
659
660 if (!page_mapped(page))
661 rc = move_to_new_page(newpage, page);
662
663 if (rc)
664 remove_migration_ptes(page, page);
665rcu_unlock:
666 if (rcu_locked)
667 rcu_read_unlock();
668
669unlock:
670
671 unlock_page(page);
672
673 if (rc != -EAGAIN) {
674
675
676
677
678
679
680 list_del(&page->lru);
681 move_to_lru(page);
682 }
683
684move_newpage:
685
686
687
688
689 move_to_lru(newpage);
690 if (result) {
691 if (rc)
692 *result = rc;
693 else
694 *result = page_to_nid(newpage);
695 }
696 return rc;
697}
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713int migrate_pages(struct list_head *from,
714 new_page_t get_new_page, unsigned long private)
715{
716 int retry = 1;
717 int nr_failed = 0;
718 int pass = 0;
719 struct page *page;
720 struct page *page2;
721 int swapwrite = current->flags & PF_SWAPWRITE;
722 int rc;
723
724 if (!swapwrite)
725 current->flags |= PF_SWAPWRITE;
726
727 for(pass = 0; pass < 10 && retry; pass++) {
728 retry = 0;
729
730 list_for_each_entry_safe(page, page2, from, lru) {
731 cond_resched();
732
733 rc = unmap_and_move(get_new_page, private,
734 page, pass > 2);
735
736 switch(rc) {
737 case -ENOMEM:
738 goto out;
739 case -EAGAIN:
740 retry++;
741 break;
742 case 0:
743 break;
744 default:
745
746 nr_failed++;
747 break;
748 }
749 }
750 }
751 rc = 0;
752out:
753 if (!swapwrite)
754 current->flags &= ~PF_SWAPWRITE;
755
756 putback_lru_pages(from);
757
758 if (rc)
759 return rc;
760
761 return nr_failed + retry;
762}
763
764#ifdef CONFIG_NUMA
765
766
767
768struct page_to_node {
769 unsigned long addr;
770 struct page *page;
771 int node;
772 int status;
773};
774
775static struct page *new_page_node(struct page *p, unsigned long private,
776 int **result)
777{
778 struct page_to_node *pm = (struct page_to_node *)private;
779
780 while (pm->node != MAX_NUMNODES && pm->page != p)
781 pm++;
782
783 if (pm->node == MAX_NUMNODES)
784 return NULL;
785
786 *result = &pm->status;
787
788 return alloc_pages_node(pm->node,
789 GFP_HIGHUSER_MOVABLE | GFP_THISNODE, 0);
790}
791
792
793
794
795
796
797static int do_move_pages(struct mm_struct *mm, struct page_to_node *pm,
798 int migrate_all)
799{
800 int err;
801 struct page_to_node *pp;
802 LIST_HEAD(pagelist);
803
804 down_read(&mm->mmap_sem);
805
806
807
808
809 migrate_prep();
810 for (pp = pm; pp->node != MAX_NUMNODES; pp++) {
811 struct vm_area_struct *vma;
812 struct page *page;
813
814
815
816
817
818 pp->page = ZERO_PAGE(0);
819
820 err = -EFAULT;
821 vma = find_vma(mm, pp->addr);
822 if (!vma || !vma_migratable(vma))
823 goto set_status;
824
825 page = follow_page(vma, pp->addr, FOLL_GET);
826 err = -ENOENT;
827 if (!page)
828 goto set_status;
829
830 if (PageReserved(page))
831 goto put_and_set;
832
833 pp->page = page;
834 err = page_to_nid(page);
835
836 if (err == pp->node)
837
838
839
840 goto put_and_set;
841
842 err = -EACCES;
843 if (page_mapcount(page) > 1 &&
844 !migrate_all)
845 goto put_and_set;
846
847 err = isolate_lru_page(page, &pagelist);
848put_and_set:
849
850
851
852
853
854 put_page(page);
855set_status:
856 pp->status = err;
857 }
858
859 if (!list_empty(&pagelist))
860 err = migrate_pages(&pagelist, new_page_node,
861 (unsigned long)pm);
862 else
863 err = -ENOENT;
864
865 up_read(&mm->mmap_sem);
866 return err;
867}
868
869
870
871
872
873
874static int do_pages_stat(struct mm_struct *mm, struct page_to_node *pm)
875{
876 down_read(&mm->mmap_sem);
877
878 for ( ; pm->node != MAX_NUMNODES; pm++) {
879 struct vm_area_struct *vma;
880 struct page *page;
881 int err;
882
883 err = -EFAULT;
884 vma = find_vma(mm, pm->addr);
885 if (!vma)
886 goto set_status;
887
888 page = follow_page(vma, pm->addr, 0);
889 err = -ENOENT;
890
891 if (!page || PageReserved(page))
892 goto set_status;
893
894 err = page_to_nid(page);
895set_status:
896 pm->status = err;
897 }
898
899 up_read(&mm->mmap_sem);
900 return 0;
901}
902
903
904
905
906
907asmlinkage long sys_move_pages(pid_t pid, unsigned long nr_pages,
908 const void __user * __user *pages,
909 const int __user *nodes,
910 int __user *status, int flags)
911{
912 int err = 0;
913 int i;
914 struct task_struct *task;
915 nodemask_t task_nodes;
916 struct mm_struct *mm;
917 struct page_to_node *pm = NULL;
918
919
920 if (flags & ~(MPOL_MF_MOVE|MPOL_MF_MOVE_ALL))
921 return -EINVAL;
922
923 if ((flags & MPOL_MF_MOVE_ALL) && !capable(CAP_SYS_NICE))
924 return -EPERM;
925
926
927 read_lock(&tasklist_lock);
928 task = pid ? find_task_by_vpid(pid) : current;
929 if (!task) {
930 read_unlock(&tasklist_lock);
931 return -ESRCH;
932 }
933 mm = get_task_mm(task);
934 read_unlock(&tasklist_lock);
935
936 if (!mm)
937 return -EINVAL;
938
939
940
941
942
943
944
945 if ((current->euid != task->suid) && (current->euid != task->uid) &&
946 (current->uid != task->suid) && (current->uid != task->uid) &&
947 !capable(CAP_SYS_NICE)) {
948 err = -EPERM;
949 goto out2;
950 }
951
952 err = security_task_movememory(task);
953 if (err)
954 goto out2;
955
956
957 task_nodes = cpuset_mems_allowed(task);
958
959
960 if (nr_pages >= ULONG_MAX / sizeof(struct page_to_node) - 1) {
961 err = -E2BIG;
962 goto out2;
963 }
964
965 pm = vmalloc((nr_pages + 1) * sizeof(struct page_to_node));
966 if (!pm) {
967 err = -ENOMEM;
968 goto out2;
969 }
970
971
972
973
974
975 for (i = 0; i < nr_pages; i++) {
976 const void __user *p;
977
978 err = -EFAULT;
979 if (get_user(p, pages + i))
980 goto out;
981
982 pm[i].addr = (unsigned long)p;
983 if (nodes) {
984 int node;
985
986 if (get_user(node, nodes + i))
987 goto out;
988
989 err = -ENODEV;
990 if (!node_state(node, N_HIGH_MEMORY))
991 goto out;
992
993 err = -EACCES;
994 if (!node_isset(node, task_nodes))
995 goto out;
996
997 pm[i].node = node;
998 } else
999 pm[i].node = 0;
1000 }
1001
1002 pm[nr_pages].node = MAX_NUMNODES;
1003
1004 if (nodes)
1005 err = do_move_pages(mm, pm, flags & MPOL_MF_MOVE_ALL);
1006 else
1007 err = do_pages_stat(mm, pm);
1008
1009 if (err >= 0)
1010
1011 for (i = 0; i < nr_pages; i++)
1012 if (put_user(pm[i].status, status + i))
1013 err = -EFAULT;
1014
1015out:
1016 vfree(pm);
1017out2:
1018 mmput(mm);
1019 return err;
1020}
1021#endif
1022
1023
1024
1025
1026
1027
1028int migrate_vmas(struct mm_struct *mm, const nodemask_t *to,
1029 const nodemask_t *from, unsigned long flags)
1030{
1031 struct vm_area_struct *vma;
1032 int err = 0;
1033
1034 for(vma = mm->mmap; vma->vm_next && !err; vma = vma->vm_next) {
1035 if (vma->vm_ops && vma->vm_ops->migrate) {
1036 err = vma->vm_ops->migrate(vma, to, from, flags);
1037 if (err)
1038 break;
1039 }
1040 }
1041 return err;
1042}
1043