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45#include <linux/mm.h>
46#include <linux/pagemap.h>
47#include <linux/swap.h>
48#include <linux/swapops.h>
49#include <linux/slab.h>
50#include <linux/init.h>
51#include <linux/ksm.h>
52#include <linux/rmap.h>
53#include <linux/rcupdate.h>
54#include <linux/export.h>
55#include <linux/memcontrol.h>
56#include <linux/mmu_notifier.h>
57#include <linux/migrate.h>
58#include <linux/hugetlb.h>
59#include <linux/backing-dev.h>
60
61#include <asm/tlbflush.h>
62
63#include "internal.h"
64
65static struct kmem_cache *anon_vma_cachep;
66static struct kmem_cache *anon_vma_chain_cachep;
67
68static inline struct anon_vma *anon_vma_alloc(void)
69{
70 struct anon_vma *anon_vma;
71
72 anon_vma = kmem_cache_alloc(anon_vma_cachep, GFP_KERNEL);
73 if (anon_vma) {
74 atomic_set(&anon_vma->refcount, 1);
75
76
77
78
79 anon_vma->root = anon_vma;
80 }
81
82 return anon_vma;
83}
84
85static inline void anon_vma_free(struct anon_vma *anon_vma)
86{
87 VM_BUG_ON(atomic_read(&anon_vma->refcount));
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106 if (rwsem_is_locked(&anon_vma->root->rwsem)) {
107 anon_vma_lock_write(anon_vma);
108 anon_vma_unlock_write(anon_vma);
109 }
110
111 kmem_cache_free(anon_vma_cachep, anon_vma);
112}
113
114static inline struct anon_vma_chain *anon_vma_chain_alloc(gfp_t gfp)
115{
116 return kmem_cache_alloc(anon_vma_chain_cachep, gfp);
117}
118
119static void anon_vma_chain_free(struct anon_vma_chain *anon_vma_chain)
120{
121 kmem_cache_free(anon_vma_chain_cachep, anon_vma_chain);
122}
123
124static void anon_vma_chain_link(struct vm_area_struct *vma,
125 struct anon_vma_chain *avc,
126 struct anon_vma *anon_vma)
127{
128 avc->vma = vma;
129 avc->anon_vma = anon_vma;
130 list_add(&avc->same_vma, &vma->anon_vma_chain);
131 anon_vma_interval_tree_insert(avc, &anon_vma->rb_root);
132}
133
134
135
136
137
138
139
140
141
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143
144
145
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147
148
149
150
151
152
153
154
155
156
157
158
159
160
161int anon_vma_prepare(struct vm_area_struct *vma)
162{
163 struct anon_vma *anon_vma = vma->anon_vma;
164 struct anon_vma_chain *avc;
165
166 might_sleep();
167 if (unlikely(!anon_vma)) {
168 struct mm_struct *mm = vma->vm_mm;
169 struct anon_vma *allocated;
170
171 avc = anon_vma_chain_alloc(GFP_KERNEL);
172 if (!avc)
173 goto out_enomem;
174
175 anon_vma = find_mergeable_anon_vma(vma);
176 allocated = NULL;
177 if (!anon_vma) {
178 anon_vma = anon_vma_alloc();
179 if (unlikely(!anon_vma))
180 goto out_enomem_free_avc;
181 allocated = anon_vma;
182 }
183
184 anon_vma_lock_write(anon_vma);
185
186 spin_lock(&mm->page_table_lock);
187 if (likely(!vma->anon_vma)) {
188 vma->anon_vma = anon_vma;
189 anon_vma_chain_link(vma, avc, anon_vma);
190 allocated = NULL;
191 avc = NULL;
192 }
193 spin_unlock(&mm->page_table_lock);
194 anon_vma_unlock_write(anon_vma);
195
196 if (unlikely(allocated))
197 put_anon_vma(allocated);
198 if (unlikely(avc))
199 anon_vma_chain_free(avc);
200 }
201 return 0;
202
203 out_enomem_free_avc:
204 anon_vma_chain_free(avc);
205 out_enomem:
206 return -ENOMEM;
207}
208
209
210
211
212
213
214
215
216
217static inline struct anon_vma *lock_anon_vma_root(struct anon_vma *root, struct anon_vma *anon_vma)
218{
219 struct anon_vma *new_root = anon_vma->root;
220 if (new_root != root) {
221 if (WARN_ON_ONCE(root))
222 up_write(&root->rwsem);
223 root = new_root;
224 down_write(&root->rwsem);
225 }
226 return root;
227}
228
229static inline void unlock_anon_vma_root(struct anon_vma *root)
230{
231 if (root)
232 up_write(&root->rwsem);
233}
234
235
236
237
238
239int anon_vma_clone(struct vm_area_struct *dst, struct vm_area_struct *src)
240{
241 struct anon_vma_chain *avc, *pavc;
242 struct anon_vma *root = NULL;
243
244 list_for_each_entry_reverse(pavc, &src->anon_vma_chain, same_vma) {
245 struct anon_vma *anon_vma;
246
247 avc = anon_vma_chain_alloc(GFP_NOWAIT | __GFP_NOWARN);
248 if (unlikely(!avc)) {
249 unlock_anon_vma_root(root);
250 root = NULL;
251 avc = anon_vma_chain_alloc(GFP_KERNEL);
252 if (!avc)
253 goto enomem_failure;
254 }
255 anon_vma = pavc->anon_vma;
256 root = lock_anon_vma_root(root, anon_vma);
257 anon_vma_chain_link(dst, avc, anon_vma);
258 }
259 unlock_anon_vma_root(root);
260 return 0;
261
262 enomem_failure:
263 unlink_anon_vmas(dst);
264 return -ENOMEM;
265}
266
267
268
269
270
271
272int anon_vma_fork(struct vm_area_struct *vma, struct vm_area_struct *pvma)
273{
274 struct anon_vma_chain *avc;
275 struct anon_vma *anon_vma;
276
277
278 if (!pvma->anon_vma)
279 return 0;
280
281
282
283
284
285 if (anon_vma_clone(vma, pvma))
286 return -ENOMEM;
287
288
289 anon_vma = anon_vma_alloc();
290 if (!anon_vma)
291 goto out_error;
292 avc = anon_vma_chain_alloc(GFP_KERNEL);
293 if (!avc)
294 goto out_error_free_anon_vma;
295
296
297
298
299
300 anon_vma->root = pvma->anon_vma->root;
301
302
303
304
305
306 get_anon_vma(anon_vma->root);
307
308 vma->anon_vma = anon_vma;
309 anon_vma_lock_write(anon_vma);
310 anon_vma_chain_link(vma, avc, anon_vma);
311 anon_vma_unlock_write(anon_vma);
312
313 return 0;
314
315 out_error_free_anon_vma:
316 put_anon_vma(anon_vma);
317 out_error:
318 unlink_anon_vmas(vma);
319 return -ENOMEM;
320}
321
322void unlink_anon_vmas(struct vm_area_struct *vma)
323{
324 struct anon_vma_chain *avc, *next;
325 struct anon_vma *root = NULL;
326
327
328
329
330
331 list_for_each_entry_safe(avc, next, &vma->anon_vma_chain, same_vma) {
332 struct anon_vma *anon_vma = avc->anon_vma;
333
334 root = lock_anon_vma_root(root, anon_vma);
335 anon_vma_interval_tree_remove(avc, &anon_vma->rb_root);
336
337
338
339
340
341 if (RB_EMPTY_ROOT(&anon_vma->rb_root))
342 continue;
343
344 list_del(&avc->same_vma);
345 anon_vma_chain_free(avc);
346 }
347 unlock_anon_vma_root(root);
348
349
350
351
352
353
354 list_for_each_entry_safe(avc, next, &vma->anon_vma_chain, same_vma) {
355 struct anon_vma *anon_vma = avc->anon_vma;
356
357 put_anon_vma(anon_vma);
358
359 list_del(&avc->same_vma);
360 anon_vma_chain_free(avc);
361 }
362}
363
364static void anon_vma_ctor(void *data)
365{
366 struct anon_vma *anon_vma = data;
367
368 init_rwsem(&anon_vma->rwsem);
369 atomic_set(&anon_vma->refcount, 0);
370 anon_vma->rb_root = RB_ROOT;
371}
372
373void __init anon_vma_init(void)
374{
375 anon_vma_cachep = kmem_cache_create("anon_vma", sizeof(struct anon_vma),
376 0, SLAB_DESTROY_BY_RCU|SLAB_PANIC, anon_vma_ctor);
377 anon_vma_chain_cachep = KMEM_CACHE(anon_vma_chain, SLAB_PANIC);
378}
379
380
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401
402
403struct anon_vma *page_get_anon_vma(struct page *page)
404{
405 struct anon_vma *anon_vma = NULL;
406 unsigned long anon_mapping;
407
408 rcu_read_lock();
409 anon_mapping = (unsigned long) ACCESS_ONCE(page->mapping);
410 if ((anon_mapping & PAGE_MAPPING_FLAGS) != PAGE_MAPPING_ANON)
411 goto out;
412 if (!page_mapped(page))
413 goto out;
414
415 anon_vma = (struct anon_vma *) (anon_mapping - PAGE_MAPPING_ANON);
416 if (!atomic_inc_not_zero(&anon_vma->refcount)) {
417 anon_vma = NULL;
418 goto out;
419 }
420
421
422
423
424
425
426
427
428 if (!page_mapped(page)) {
429 put_anon_vma(anon_vma);
430 anon_vma = NULL;
431 }
432out:
433 rcu_read_unlock();
434
435 return anon_vma;
436}
437
438
439
440
441
442
443
444
445struct anon_vma *page_lock_anon_vma_read(struct page *page)
446{
447 struct anon_vma *anon_vma = NULL;
448 struct anon_vma *root_anon_vma;
449 unsigned long anon_mapping;
450
451 rcu_read_lock();
452 anon_mapping = (unsigned long) ACCESS_ONCE(page->mapping);
453 if ((anon_mapping & PAGE_MAPPING_FLAGS) != PAGE_MAPPING_ANON)
454 goto out;
455 if (!page_mapped(page))
456 goto out;
457
458 anon_vma = (struct anon_vma *) (anon_mapping - PAGE_MAPPING_ANON);
459 root_anon_vma = ACCESS_ONCE(anon_vma->root);
460 if (down_read_trylock(&root_anon_vma->rwsem)) {
461
462
463
464
465
466 if (!page_mapped(page)) {
467 up_read(&root_anon_vma->rwsem);
468 anon_vma = NULL;
469 }
470 goto out;
471 }
472
473
474 if (!atomic_inc_not_zero(&anon_vma->refcount)) {
475 anon_vma = NULL;
476 goto out;
477 }
478
479 if (!page_mapped(page)) {
480 put_anon_vma(anon_vma);
481 anon_vma = NULL;
482 goto out;
483 }
484
485
486 rcu_read_unlock();
487 anon_vma_lock_read(anon_vma);
488
489 if (atomic_dec_and_test(&anon_vma->refcount)) {
490
491
492
493
494
495 anon_vma_unlock_read(anon_vma);
496 __put_anon_vma(anon_vma);
497 anon_vma = NULL;
498 }
499
500 return anon_vma;
501
502out:
503 rcu_read_unlock();
504 return anon_vma;
505}
506
507void page_unlock_anon_vma_read(struct anon_vma *anon_vma)
508{
509 anon_vma_unlock_read(anon_vma);
510}
511
512
513
514
515static inline unsigned long
516__vma_address(struct page *page, struct vm_area_struct *vma)
517{
518 pgoff_t pgoff = page->index << (PAGE_CACHE_SHIFT - PAGE_SHIFT);
519
520 if (unlikely(is_vm_hugetlb_page(vma)))
521 pgoff = page->index << huge_page_order(page_hstate(page));
522
523 return vma->vm_start + ((pgoff - vma->vm_pgoff) << PAGE_SHIFT);
524}
525
526inline unsigned long
527vma_address(struct page *page, struct vm_area_struct *vma)
528{
529 unsigned long address = __vma_address(page, vma);
530
531
532 VM_BUG_ON(address < vma->vm_start || address >= vma->vm_end);
533
534 return address;
535}
536
537
538
539
540
541unsigned long page_address_in_vma(struct page *page, struct vm_area_struct *vma)
542{
543 unsigned long address;
544 if (PageAnon(page)) {
545 struct anon_vma *page__anon_vma = page_anon_vma(page);
546
547
548
549
550 if (!vma->anon_vma || !page__anon_vma ||
551 vma->anon_vma->root != page__anon_vma->root)
552 return -EFAULT;
553 } else if (page->mapping && !(vma->vm_flags & VM_NONLINEAR)) {
554 if (!vma->vm_file ||
555 vma->vm_file->f_mapping != page->mapping)
556 return -EFAULT;
557 } else
558 return -EFAULT;
559 address = __vma_address(page, vma);
560 if (unlikely(address < vma->vm_start || address >= vma->vm_end))
561 return -EFAULT;
562 return address;
563}
564
565pmd_t *mm_find_pmd(struct mm_struct *mm, unsigned long address)
566{
567 pgd_t *pgd;
568 pud_t *pud;
569 pmd_t *pmd = NULL;
570
571 pgd = pgd_offset(mm, address);
572 if (!pgd_present(*pgd))
573 goto out;
574
575 pud = pud_offset(pgd, address);
576 if (!pud_present(*pud))
577 goto out;
578
579 pmd = pmd_offset(pud, address);
580 if (!pmd_present(*pmd))
581 pmd = NULL;
582out:
583 return pmd;
584}
585
586
587
588
589
590
591
592
593
594
595pte_t *__page_check_address(struct page *page, struct mm_struct *mm,
596 unsigned long address, spinlock_t **ptlp, int sync)
597{
598 pmd_t *pmd;
599 pte_t *pte;
600 spinlock_t *ptl;
601
602 if (unlikely(PageHuge(page))) {
603 pte = huge_pte_offset(mm, address);
604 ptl = &mm->page_table_lock;
605 goto check;
606 }
607
608 pmd = mm_find_pmd(mm, address);
609 if (!pmd)
610 return NULL;
611
612 if (pmd_trans_huge(*pmd))
613 return NULL;
614
615 pte = pte_offset_map(pmd, address);
616
617 if (!sync && !pte_present(*pte)) {
618 pte_unmap(pte);
619 return NULL;
620 }
621
622 ptl = pte_lockptr(mm, pmd);
623check:
624 spin_lock(ptl);
625 if (pte_present(*pte) && page_to_pfn(page) == pte_pfn(*pte)) {
626 *ptlp = ptl;
627 return pte;
628 }
629 pte_unmap_unlock(pte, ptl);
630 return NULL;
631}
632
633
634
635
636
637
638
639
640
641
642int page_mapped_in_vma(struct page *page, struct vm_area_struct *vma)
643{
644 unsigned long address;
645 pte_t *pte;
646 spinlock_t *ptl;
647
648 address = __vma_address(page, vma);
649 if (unlikely(address < vma->vm_start || address >= vma->vm_end))
650 return 0;
651 pte = page_check_address(page, vma->vm_mm, address, &ptl, 1);
652 if (!pte)
653 return 0;
654 pte_unmap_unlock(pte, ptl);
655
656 return 1;
657}
658
659
660
661
662
663int page_referenced_one(struct page *page, struct vm_area_struct *vma,
664 unsigned long address, unsigned int *mapcount,
665 unsigned long *vm_flags)
666{
667 struct mm_struct *mm = vma->vm_mm;
668 int referenced = 0;
669
670 if (unlikely(PageTransHuge(page))) {
671 pmd_t *pmd;
672
673 spin_lock(&mm->page_table_lock);
674
675
676
677
678 pmd = page_check_address_pmd(page, mm, address,
679 PAGE_CHECK_ADDRESS_PMD_FLAG);
680 if (!pmd) {
681 spin_unlock(&mm->page_table_lock);
682 goto out;
683 }
684
685 if (vma->vm_flags & VM_LOCKED) {
686 spin_unlock(&mm->page_table_lock);
687 *mapcount = 0;
688 *vm_flags |= VM_LOCKED;
689 goto out;
690 }
691
692
693 if (pmdp_clear_flush_young_notify(vma, address, pmd))
694 referenced++;
695 spin_unlock(&mm->page_table_lock);
696 } else {
697 pte_t *pte;
698 spinlock_t *ptl;
699
700
701
702
703
704 pte = page_check_address(page, mm, address, &ptl, 0);
705 if (!pte)
706 goto out;
707
708 if (vma->vm_flags & VM_LOCKED) {
709 pte_unmap_unlock(pte, ptl);
710 *mapcount = 0;
711 *vm_flags |= VM_LOCKED;
712 goto out;
713 }
714
715 if (ptep_clear_flush_young_notify(vma, address, pte)) {
716
717
718
719
720
721
722
723 if (likely(!(vma->vm_flags & VM_SEQ_READ)))
724 referenced++;
725 }
726 pte_unmap_unlock(pte, ptl);
727 }
728
729 (*mapcount)--;
730
731 if (referenced)
732 *vm_flags |= vma->vm_flags;
733out:
734 return referenced;
735}
736
737static int page_referenced_anon(struct page *page,
738 struct mem_cgroup *memcg,
739 unsigned long *vm_flags)
740{
741 unsigned int mapcount;
742 struct anon_vma *anon_vma;
743 pgoff_t pgoff;
744 struct anon_vma_chain *avc;
745 int referenced = 0;
746
747 anon_vma = page_lock_anon_vma_read(page);
748 if (!anon_vma)
749 return referenced;
750
751 mapcount = page_mapcount(page);
752 pgoff = page->index << (PAGE_CACHE_SHIFT - PAGE_SHIFT);
753 anon_vma_interval_tree_foreach(avc, &anon_vma->rb_root, pgoff, pgoff) {
754 struct vm_area_struct *vma = avc->vma;
755 unsigned long address = vma_address(page, vma);
756
757
758
759
760
761 if (memcg && !mm_match_cgroup(vma->vm_mm, memcg))
762 continue;
763 referenced += page_referenced_one(page, vma, address,
764 &mapcount, vm_flags);
765 if (!mapcount)
766 break;
767 }
768
769 page_unlock_anon_vma_read(anon_vma);
770 return referenced;
771}
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786static int page_referenced_file(struct page *page,
787 struct mem_cgroup *memcg,
788 unsigned long *vm_flags)
789{
790 unsigned int mapcount;
791 struct address_space *mapping = page->mapping;
792 pgoff_t pgoff = page->index << (PAGE_CACHE_SHIFT - PAGE_SHIFT);
793 struct vm_area_struct *vma;
794 int referenced = 0;
795
796
797
798
799
800
801 BUG_ON(PageAnon(page));
802
803
804
805
806
807
808
809 BUG_ON(!PageLocked(page));
810
811 mutex_lock(&mapping->i_mmap_mutex);
812
813
814
815
816
817 mapcount = page_mapcount(page);
818
819 vma_interval_tree_foreach(vma, &mapping->i_mmap, pgoff, pgoff) {
820 unsigned long address = vma_address(page, vma);
821
822
823
824
825
826 if (memcg && !mm_match_cgroup(vma->vm_mm, memcg))
827 continue;
828 referenced += page_referenced_one(page, vma, address,
829 &mapcount, vm_flags);
830 if (!mapcount)
831 break;
832 }
833
834 mutex_unlock(&mapping->i_mmap_mutex);
835 return referenced;
836}
837
838
839
840
841
842
843
844
845
846
847
848int page_referenced(struct page *page,
849 int is_locked,
850 struct mem_cgroup *memcg,
851 unsigned long *vm_flags)
852{
853 int referenced = 0;
854 int we_locked = 0;
855
856 *vm_flags = 0;
857 if (page_mapped(page) && page_rmapping(page)) {
858 if (!is_locked && (!PageAnon(page) || PageKsm(page))) {
859 we_locked = trylock_page(page);
860 if (!we_locked) {
861 referenced++;
862 goto out;
863 }
864 }
865 if (unlikely(PageKsm(page)))
866 referenced += page_referenced_ksm(page, memcg,
867 vm_flags);
868 else if (PageAnon(page))
869 referenced += page_referenced_anon(page, memcg,
870 vm_flags);
871 else if (page->mapping)
872 referenced += page_referenced_file(page, memcg,
873 vm_flags);
874 if (we_locked)
875 unlock_page(page);
876
877 if (page_test_and_clear_young(page_to_pfn(page)))
878 referenced++;
879 }
880out:
881 return referenced;
882}
883
884static int page_mkclean_one(struct page *page, struct vm_area_struct *vma,
885 unsigned long address)
886{
887 struct mm_struct *mm = vma->vm_mm;
888 pte_t *pte;
889 spinlock_t *ptl;
890 int ret = 0;
891
892 pte = page_check_address(page, mm, address, &ptl, 1);
893 if (!pte)
894 goto out;
895
896 if (pte_dirty(*pte) || pte_write(*pte)) {
897 pte_t entry;
898
899 flush_cache_page(vma, address, pte_pfn(*pte));
900 entry = ptep_clear_flush(vma, address, pte);
901 entry = pte_wrprotect(entry);
902 entry = pte_mkclean(entry);
903 set_pte_at(mm, address, pte, entry);
904 ret = 1;
905 }
906
907 pte_unmap_unlock(pte, ptl);
908
909 if (ret)
910 mmu_notifier_invalidate_page(mm, address);
911out:
912 return ret;
913}
914
915static int page_mkclean_file(struct address_space *mapping, struct page *page)
916{
917 pgoff_t pgoff = page->index << (PAGE_CACHE_SHIFT - PAGE_SHIFT);
918 struct vm_area_struct *vma;
919 int ret = 0;
920
921 BUG_ON(PageAnon(page));
922
923 mutex_lock(&mapping->i_mmap_mutex);
924 vma_interval_tree_foreach(vma, &mapping->i_mmap, pgoff, pgoff) {
925 if (vma->vm_flags & VM_SHARED) {
926 unsigned long address = vma_address(page, vma);
927 ret += page_mkclean_one(page, vma, address);
928 }
929 }
930 mutex_unlock(&mapping->i_mmap_mutex);
931 return ret;
932}
933
934int page_mkclean(struct page *page)
935{
936 int ret = 0;
937
938 BUG_ON(!PageLocked(page));
939
940 if (page_mapped(page)) {
941 struct address_space *mapping = page_mapping(page);
942 if (mapping)
943 ret = page_mkclean_file(mapping, page);
944 }
945
946 return ret;
947}
948EXPORT_SYMBOL_GPL(page_mkclean);
949
950
951
952
953
954
955
956
957
958
959
960
961void page_move_anon_rmap(struct page *page,
962 struct vm_area_struct *vma, unsigned long address)
963{
964 struct anon_vma *anon_vma = vma->anon_vma;
965
966 VM_BUG_ON(!PageLocked(page));
967 VM_BUG_ON(!anon_vma);
968 VM_BUG_ON(page->index != linear_page_index(vma, address));
969
970 anon_vma = (void *) anon_vma + PAGE_MAPPING_ANON;
971 page->mapping = (struct address_space *) anon_vma;
972}
973
974
975
976
977
978
979
980
981static void __page_set_anon_rmap(struct page *page,
982 struct vm_area_struct *vma, unsigned long address, int exclusive)
983{
984 struct anon_vma *anon_vma = vma->anon_vma;
985
986 BUG_ON(!anon_vma);
987
988 if (PageAnon(page))
989 return;
990
991
992
993
994
995
996 if (!exclusive)
997 anon_vma = anon_vma->root;
998
999 anon_vma = (void *) anon_vma + PAGE_MAPPING_ANON;
1000 page->mapping = (struct address_space *) anon_vma;
1001 page->index = linear_page_index(vma, address);
1002}
1003
1004
1005
1006
1007
1008
1009
1010static void __page_check_anon_rmap(struct page *page,
1011 struct vm_area_struct *vma, unsigned long address)
1012{
1013#ifdef CONFIG_DEBUG_VM
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026 BUG_ON(page_anon_vma(page)->root != vma->anon_vma->root);
1027 BUG_ON(page->index != linear_page_index(vma, address));
1028#endif
1029}
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042void page_add_anon_rmap(struct page *page,
1043 struct vm_area_struct *vma, unsigned long address)
1044{
1045 do_page_add_anon_rmap(page, vma, address, 0);
1046}
1047
1048
1049
1050
1051
1052
1053void do_page_add_anon_rmap(struct page *page,
1054 struct vm_area_struct *vma, unsigned long address, int exclusive)
1055{
1056 int first = atomic_inc_and_test(&page->_mapcount);
1057 if (first) {
1058 if (!PageTransHuge(page))
1059 __inc_zone_page_state(page, NR_ANON_PAGES);
1060 else
1061 __inc_zone_page_state(page,
1062 NR_ANON_TRANSPARENT_HUGEPAGES);
1063 }
1064 if (unlikely(PageKsm(page)))
1065 return;
1066
1067 VM_BUG_ON(!PageLocked(page));
1068
1069 if (first)
1070 __page_set_anon_rmap(page, vma, address, exclusive);
1071 else
1072 __page_check_anon_rmap(page, vma, address);
1073}
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085void page_add_new_anon_rmap(struct page *page,
1086 struct vm_area_struct *vma, unsigned long address)
1087{
1088 VM_BUG_ON(address < vma->vm_start || address >= vma->vm_end);
1089 SetPageSwapBacked(page);
1090 atomic_set(&page->_mapcount, 0);
1091 if (!PageTransHuge(page))
1092 __inc_zone_page_state(page, NR_ANON_PAGES);
1093 else
1094 __inc_zone_page_state(page, NR_ANON_TRANSPARENT_HUGEPAGES);
1095 __page_set_anon_rmap(page, vma, address, 1);
1096 if (!mlocked_vma_newpage(vma, page)) {
1097 SetPageActive(page);
1098 lru_cache_add(page);
1099 } else
1100 add_page_to_unevictable_list(page);
1101}
1102
1103
1104
1105
1106
1107
1108
1109void page_add_file_rmap(struct page *page)
1110{
1111 bool locked;
1112 unsigned long flags;
1113
1114 mem_cgroup_begin_update_page_stat(page, &locked, &flags);
1115 if (atomic_inc_and_test(&page->_mapcount)) {
1116 __inc_zone_page_state(page, NR_FILE_MAPPED);
1117 mem_cgroup_inc_page_stat(page, MEMCG_NR_FILE_MAPPED);
1118 }
1119 mem_cgroup_end_update_page_stat(page, &locked, &flags);
1120}
1121
1122
1123
1124
1125
1126
1127
1128void page_remove_rmap(struct page *page)
1129{
1130 bool anon = PageAnon(page);
1131 bool locked;
1132 unsigned long flags;
1133
1134
1135
1136
1137
1138
1139 if (!anon)
1140 mem_cgroup_begin_update_page_stat(page, &locked, &flags);
1141
1142
1143 if (!atomic_add_negative(-1, &page->_mapcount))
1144 goto out;
1145
1146
1147
1148
1149
1150 if (unlikely(PageHuge(page)))
1151 goto out;
1152 if (anon) {
1153 mem_cgroup_uncharge_page(page);
1154 if (!PageTransHuge(page))
1155 __dec_zone_page_state(page, NR_ANON_PAGES);
1156 else
1157 __dec_zone_page_state(page,
1158 NR_ANON_TRANSPARENT_HUGEPAGES);
1159 } else {
1160 __dec_zone_page_state(page, NR_FILE_MAPPED);
1161 mem_cgroup_dec_page_stat(page, MEMCG_NR_FILE_MAPPED);
1162 mem_cgroup_end_update_page_stat(page, &locked, &flags);
1163 }
1164 if (unlikely(PageMlocked(page)))
1165 clear_page_mlock(page);
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175 return;
1176out:
1177 if (!anon)
1178 mem_cgroup_end_update_page_stat(page, &locked, &flags);
1179}
1180
1181
1182
1183
1184
1185int try_to_unmap_one(struct page *page, struct vm_area_struct *vma,
1186 unsigned long address, enum ttu_flags flags)
1187{
1188 struct mm_struct *mm = vma->vm_mm;
1189 pte_t *pte;
1190 pte_t pteval;
1191 spinlock_t *ptl;
1192 int ret = SWAP_AGAIN;
1193
1194 pte = page_check_address(page, mm, address, &ptl, 0);
1195 if (!pte)
1196 goto out;
1197
1198
1199
1200
1201
1202
1203 if (!(flags & TTU_IGNORE_MLOCK)) {
1204 if (vma->vm_flags & VM_LOCKED)
1205 goto out_mlock;
1206
1207 if (TTU_ACTION(flags) == TTU_MUNLOCK)
1208 goto out_unmap;
1209 }
1210 if (!(flags & TTU_IGNORE_ACCESS)) {
1211 if (ptep_clear_flush_young_notify(vma, address, pte)) {
1212 ret = SWAP_FAIL;
1213 goto out_unmap;
1214 }
1215 }
1216
1217
1218 flush_cache_page(vma, address, page_to_pfn(page));
1219 pteval = ptep_clear_flush(vma, address, pte);
1220
1221
1222 if (pte_dirty(pteval))
1223 set_page_dirty(page);
1224
1225
1226 update_hiwater_rss(mm);
1227
1228 if (PageHWPoison(page) && !(flags & TTU_IGNORE_HWPOISON)) {
1229 if (!PageHuge(page)) {
1230 if (PageAnon(page))
1231 dec_mm_counter(mm, MM_ANONPAGES);
1232 else
1233 dec_mm_counter(mm, MM_FILEPAGES);
1234 }
1235 set_pte_at(mm, address, pte,
1236 swp_entry_to_pte(make_hwpoison_entry(page)));
1237 } else if (PageAnon(page)) {
1238 swp_entry_t entry = { .val = page_private(page) };
1239 pte_t swp_pte;
1240
1241 if (PageSwapCache(page)) {
1242
1243
1244
1245
1246 if (swap_duplicate(entry) < 0) {
1247 set_pte_at(mm, address, pte, pteval);
1248 ret = SWAP_FAIL;
1249 goto out_unmap;
1250 }
1251 if (list_empty(&mm->mmlist)) {
1252 spin_lock(&mmlist_lock);
1253 if (list_empty(&mm->mmlist))
1254 list_add(&mm->mmlist, &init_mm.mmlist);
1255 spin_unlock(&mmlist_lock);
1256 }
1257 dec_mm_counter(mm, MM_ANONPAGES);
1258 inc_mm_counter(mm, MM_SWAPENTS);
1259 } else if (IS_ENABLED(CONFIG_MIGRATION)) {
1260
1261
1262
1263
1264
1265 BUG_ON(TTU_ACTION(flags) != TTU_MIGRATION);
1266 entry = make_migration_entry(page, pte_write(pteval));
1267 }
1268 swp_pte = swp_entry_to_pte(entry);
1269 if (pte_soft_dirty(pteval))
1270 swp_pte = pte_swp_mksoft_dirty(swp_pte);
1271 set_pte_at(mm, address, pte, swp_pte);
1272 BUG_ON(pte_file(*pte));
1273 } else if (IS_ENABLED(CONFIG_MIGRATION) &&
1274 (TTU_ACTION(flags) == TTU_MIGRATION)) {
1275
1276 swp_entry_t entry;
1277 entry = make_migration_entry(page, pte_write(pteval));
1278 set_pte_at(mm, address, pte, swp_entry_to_pte(entry));
1279 } else
1280 dec_mm_counter(mm, MM_FILEPAGES);
1281
1282 page_remove_rmap(page);
1283 page_cache_release(page);
1284
1285out_unmap:
1286 pte_unmap_unlock(pte, ptl);
1287 if (ret != SWAP_FAIL)
1288 mmu_notifier_invalidate_page(mm, address);
1289out:
1290 return ret;
1291
1292out_mlock:
1293 pte_unmap_unlock(pte, ptl);
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304 if (down_read_trylock(&vma->vm_mm->mmap_sem)) {
1305 if (vma->vm_flags & VM_LOCKED) {
1306 mlock_vma_page(page);
1307 ret = SWAP_MLOCK;
1308 }
1309 up_read(&vma->vm_mm->mmap_sem);
1310 }
1311 return ret;
1312}
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338#define CLUSTER_SIZE min(32*PAGE_SIZE, PMD_SIZE)
1339#define CLUSTER_MASK (~(CLUSTER_SIZE - 1))
1340
1341static int try_to_unmap_cluster(unsigned long cursor, unsigned int *mapcount,
1342 struct vm_area_struct *vma, struct page *check_page)
1343{
1344 struct mm_struct *mm = vma->vm_mm;
1345 pmd_t *pmd;
1346 pte_t *pte;
1347 pte_t pteval;
1348 spinlock_t *ptl;
1349 struct page *page;
1350 unsigned long address;
1351 unsigned long mmun_start;
1352 unsigned long mmun_end;
1353 unsigned long end;
1354 int ret = SWAP_AGAIN;
1355 int locked_vma = 0;
1356
1357 address = (vma->vm_start + cursor) & CLUSTER_MASK;
1358 end = address + CLUSTER_SIZE;
1359 if (address < vma->vm_start)
1360 address = vma->vm_start;
1361 if (end > vma->vm_end)
1362 end = vma->vm_end;
1363
1364 pmd = mm_find_pmd(mm, address);
1365 if (!pmd)
1366 return ret;
1367
1368 mmun_start = address;
1369 mmun_end = end;
1370 mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end);
1371
1372
1373
1374
1375
1376 if (down_read_trylock(&vma->vm_mm->mmap_sem)) {
1377 locked_vma = (vma->vm_flags & VM_LOCKED);
1378 if (!locked_vma)
1379 up_read(&vma->vm_mm->mmap_sem);
1380 }
1381
1382 pte = pte_offset_map_lock(mm, pmd, address, &ptl);
1383
1384
1385 update_hiwater_rss(mm);
1386
1387 for (; address < end; pte++, address += PAGE_SIZE) {
1388 if (!pte_present(*pte))
1389 continue;
1390 page = vm_normal_page(vma, address, *pte);
1391 BUG_ON(!page || PageAnon(page));
1392
1393 if (locked_vma) {
1394 mlock_vma_page(page);
1395 if (page == check_page)
1396 ret = SWAP_MLOCK;
1397 continue;
1398 }
1399
1400 if (ptep_clear_flush_young_notify(vma, address, pte))
1401 continue;
1402
1403
1404 flush_cache_page(vma, address, pte_pfn(*pte));
1405 pteval = ptep_clear_flush(vma, address, pte);
1406
1407
1408 if (page->index != linear_page_index(vma, address)) {
1409 pte_t ptfile = pgoff_to_pte(page->index);
1410 if (pte_soft_dirty(pteval))
1411 pte_file_mksoft_dirty(ptfile);
1412 set_pte_at(mm, address, pte, ptfile);
1413 }
1414
1415
1416 if (pte_dirty(pteval))
1417 set_page_dirty(page);
1418
1419 page_remove_rmap(page);
1420 page_cache_release(page);
1421 dec_mm_counter(mm, MM_FILEPAGES);
1422 (*mapcount)--;
1423 }
1424 pte_unmap_unlock(pte - 1, ptl);
1425 mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end);
1426 if (locked_vma)
1427 up_read(&vma->vm_mm->mmap_sem);
1428 return ret;
1429}
1430
1431bool is_vma_temporary_stack(struct vm_area_struct *vma)
1432{
1433 int maybe_stack = vma->vm_flags & (VM_GROWSDOWN | VM_GROWSUP);
1434
1435 if (!maybe_stack)
1436 return false;
1437
1438 if ((vma->vm_flags & VM_STACK_INCOMPLETE_SETUP) ==
1439 VM_STACK_INCOMPLETE_SETUP)
1440 return true;
1441
1442 return false;
1443}
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461static int try_to_unmap_anon(struct page *page, enum ttu_flags flags)
1462{
1463 struct anon_vma *anon_vma;
1464 pgoff_t pgoff;
1465 struct anon_vma_chain *avc;
1466 int ret = SWAP_AGAIN;
1467
1468 anon_vma = page_lock_anon_vma_read(page);
1469 if (!anon_vma)
1470 return ret;
1471
1472 pgoff = page->index << (PAGE_CACHE_SHIFT - PAGE_SHIFT);
1473 anon_vma_interval_tree_foreach(avc, &anon_vma->rb_root, pgoff, pgoff) {
1474 struct vm_area_struct *vma = avc->vma;
1475 unsigned long address;
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485 if (IS_ENABLED(CONFIG_MIGRATION) && (flags & TTU_MIGRATION) &&
1486 is_vma_temporary_stack(vma))
1487 continue;
1488
1489 address = vma_address(page, vma);
1490 ret = try_to_unmap_one(page, vma, address, flags);
1491 if (ret != SWAP_AGAIN || !page_mapped(page))
1492 break;
1493 }
1494
1495 page_unlock_anon_vma_read(anon_vma);
1496 return ret;
1497}
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514static int try_to_unmap_file(struct page *page, enum ttu_flags flags)
1515{
1516 struct address_space *mapping = page->mapping;
1517 pgoff_t pgoff = page->index << (PAGE_CACHE_SHIFT - PAGE_SHIFT);
1518 struct vm_area_struct *vma;
1519 int ret = SWAP_AGAIN;
1520 unsigned long cursor;
1521 unsigned long max_nl_cursor = 0;
1522 unsigned long max_nl_size = 0;
1523 unsigned int mapcount;
1524
1525 if (PageHuge(page))
1526 pgoff = page->index << compound_order(page);
1527
1528 mutex_lock(&mapping->i_mmap_mutex);
1529 vma_interval_tree_foreach(vma, &mapping->i_mmap, pgoff, pgoff) {
1530 unsigned long address = vma_address(page, vma);
1531 ret = try_to_unmap_one(page, vma, address, flags);
1532 if (ret != SWAP_AGAIN || !page_mapped(page))
1533 goto out;
1534 }
1535
1536 if (list_empty(&mapping->i_mmap_nonlinear))
1537 goto out;
1538
1539
1540
1541
1542
1543
1544 if (TTU_ACTION(flags) == TTU_MUNLOCK)
1545 goto out;
1546
1547 list_for_each_entry(vma, &mapping->i_mmap_nonlinear,
1548 shared.nonlinear) {
1549 cursor = (unsigned long) vma->vm_private_data;
1550 if (cursor > max_nl_cursor)
1551 max_nl_cursor = cursor;
1552 cursor = vma->vm_end - vma->vm_start;
1553 if (cursor > max_nl_size)
1554 max_nl_size = cursor;
1555 }
1556
1557 if (max_nl_size == 0) {
1558 ret = SWAP_FAIL;
1559 goto out;
1560 }
1561
1562
1563
1564
1565
1566
1567
1568
1569 mapcount = page_mapcount(page);
1570 if (!mapcount)
1571 goto out;
1572 cond_resched();
1573
1574 max_nl_size = (max_nl_size + CLUSTER_SIZE - 1) & CLUSTER_MASK;
1575 if (max_nl_cursor == 0)
1576 max_nl_cursor = CLUSTER_SIZE;
1577
1578 do {
1579 list_for_each_entry(vma, &mapping->i_mmap_nonlinear,
1580 shared.nonlinear) {
1581 cursor = (unsigned long) vma->vm_private_data;
1582 while ( cursor < max_nl_cursor &&
1583 cursor < vma->vm_end - vma->vm_start) {
1584 if (try_to_unmap_cluster(cursor, &mapcount,
1585 vma, page) == SWAP_MLOCK)
1586 ret = SWAP_MLOCK;
1587 cursor += CLUSTER_SIZE;
1588 vma->vm_private_data = (void *) cursor;
1589 if ((int)mapcount <= 0)
1590 goto out;
1591 }
1592 vma->vm_private_data = (void *) max_nl_cursor;
1593 }
1594 cond_resched();
1595 max_nl_cursor += CLUSTER_SIZE;
1596 } while (max_nl_cursor <= max_nl_size);
1597
1598
1599
1600
1601
1602
1603 list_for_each_entry(vma, &mapping->i_mmap_nonlinear, shared.nonlinear)
1604 vma->vm_private_data = NULL;
1605out:
1606 mutex_unlock(&mapping->i_mmap_mutex);
1607 return ret;
1608}
1609
1610
1611
1612
1613
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624int try_to_unmap(struct page *page, enum ttu_flags flags)
1625{
1626 int ret;
1627
1628 BUG_ON(!PageLocked(page));
1629 VM_BUG_ON(!PageHuge(page) && PageTransHuge(page));
1630
1631 if (unlikely(PageKsm(page)))
1632 ret = try_to_unmap_ksm(page, flags);
1633 else if (PageAnon(page))
1634 ret = try_to_unmap_anon(page, flags);
1635 else
1636 ret = try_to_unmap_file(page, flags);
1637 if (ret != SWAP_MLOCK && !page_mapped(page))
1638 ret = SWAP_SUCCESS;
1639 return ret;
1640}
1641
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
1657int try_to_munlock(struct page *page)
1658{
1659 VM_BUG_ON(!PageLocked(page) || PageLRU(page));
1660
1661 if (unlikely(PageKsm(page)))
1662 return try_to_unmap_ksm(page, TTU_MUNLOCK);
1663 else if (PageAnon(page))
1664 return try_to_unmap_anon(page, TTU_MUNLOCK);
1665 else
1666 return try_to_unmap_file(page, TTU_MUNLOCK);
1667}
1668
1669void __put_anon_vma(struct anon_vma *anon_vma)
1670{
1671 struct anon_vma *root = anon_vma->root;
1672
1673 if (root != anon_vma && atomic_dec_and_test(&root->refcount))
1674 anon_vma_free(root);
1675
1676 anon_vma_free(anon_vma);
1677}
1678
1679#ifdef CONFIG_MIGRATION
1680
1681
1682
1683
1684static int rmap_walk_anon(struct page *page, int (*rmap_one)(struct page *,
1685 struct vm_area_struct *, unsigned long, void *), void *arg)
1686{
1687 struct anon_vma *anon_vma;
1688 pgoff_t pgoff = page->index << (PAGE_CACHE_SHIFT - PAGE_SHIFT);
1689 struct anon_vma_chain *avc;
1690 int ret = SWAP_AGAIN;
1691
1692
1693
1694
1695
1696
1697
1698 anon_vma = page_anon_vma(page);
1699 if (!anon_vma)
1700 return ret;
1701 anon_vma_lock_read(anon_vma);
1702 anon_vma_interval_tree_foreach(avc, &anon_vma->rb_root, pgoff, pgoff) {
1703 struct vm_area_struct *vma = avc->vma;
1704 unsigned long address = vma_address(page, vma);
1705 ret = rmap_one(page, vma, address, arg);
1706 if (ret != SWAP_AGAIN)
1707 break;
1708 }
1709 anon_vma_unlock_read(anon_vma);
1710 return ret;
1711}
1712
1713static int rmap_walk_file(struct page *page, int (*rmap_one)(struct page *,
1714 struct vm_area_struct *, unsigned long, void *), void *arg)
1715{
1716 struct address_space *mapping = page->mapping;
1717 pgoff_t pgoff = page->index << (PAGE_CACHE_SHIFT - PAGE_SHIFT);
1718 struct vm_area_struct *vma;
1719 int ret = SWAP_AGAIN;
1720
1721 if (!mapping)
1722 return ret;
1723 mutex_lock(&mapping->i_mmap_mutex);
1724 vma_interval_tree_foreach(vma, &mapping->i_mmap, pgoff, pgoff) {
1725 unsigned long address = vma_address(page, vma);
1726 ret = rmap_one(page, vma, address, arg);
1727 if (ret != SWAP_AGAIN)
1728 break;
1729 }
1730
1731
1732
1733
1734
1735 mutex_unlock(&mapping->i_mmap_mutex);
1736 return ret;
1737}
1738
1739int rmap_walk(struct page *page, int (*rmap_one)(struct page *,
1740 struct vm_area_struct *, unsigned long, void *), void *arg)
1741{
1742 VM_BUG_ON(!PageLocked(page));
1743
1744 if (unlikely(PageKsm(page)))
1745 return rmap_walk_ksm(page, rmap_one, arg);
1746 else if (PageAnon(page))
1747 return rmap_walk_anon(page, rmap_one, arg);
1748 else
1749 return rmap_walk_file(page, rmap_one, arg);
1750}
1751#endif
1752
1753#ifdef CONFIG_HUGETLB_PAGE
1754
1755
1756
1757
1758
1759static void __hugepage_set_anon_rmap(struct page *page,
1760 struct vm_area_struct *vma, unsigned long address, int exclusive)
1761{
1762 struct anon_vma *anon_vma = vma->anon_vma;
1763
1764 BUG_ON(!anon_vma);
1765
1766 if (PageAnon(page))
1767 return;
1768 if (!exclusive)
1769 anon_vma = anon_vma->root;
1770
1771 anon_vma = (void *) anon_vma + PAGE_MAPPING_ANON;
1772 page->mapping = (struct address_space *) anon_vma;
1773 page->index = linear_page_index(vma, address);
1774}
1775
1776void hugepage_add_anon_rmap(struct page *page,
1777 struct vm_area_struct *vma, unsigned long address)
1778{
1779 struct anon_vma *anon_vma = vma->anon_vma;
1780 int first;
1781
1782 BUG_ON(!PageLocked(page));
1783 BUG_ON(!anon_vma);
1784
1785 first = atomic_inc_and_test(&page->_mapcount);
1786 if (first)
1787 __hugepage_set_anon_rmap(page, vma, address, 0);
1788}
1789
1790void hugepage_add_new_anon_rmap(struct page *page,
1791 struct vm_area_struct *vma, unsigned long address)
1792{
1793 BUG_ON(address < vma->vm_start || address >= vma->vm_end);
1794 atomic_set(&page->_mapcount, 0);
1795 __hugepage_set_anon_rmap(page, vma, address, 1);
1796}
1797#endif
1798