2 * mm/rmap.c - physical to virtual reverse mappings
4 * Copyright 2001, Rik van Riel <riel@conectiva.com.br>
5 * Released under the General Public License (GPL).
7 * Simple, low overhead reverse mapping scheme.
8 * Please try to keep this thing as modular as possible.
10 * Provides methods for unmapping each kind of mapped page:
11 * the anon methods track anonymous pages, and
12 * the file methods track pages belonging to an inode.
14 * Original design by Rik van Riel <riel@conectiva.com.br> 2001
15 * File methods by Dave McCracken <dmccr@us.ibm.com> 2003, 2004
16 * Anonymous methods by Andrea Arcangeli <andrea@suse.de> 2004
17 * Contributions by Hugh Dickins 2003, 2004
21 * Lock ordering in mm:
23 * inode->i_mutex (while writing or truncating, not reading or faulting)
25 * page->flags PG_locked (lock_page)
26 * mapping->i_mmap_rwsem
28 * mm->page_table_lock or pte_lock
29 * zone->lru_lock (in mark_page_accessed, isolate_lru_page)
30 * swap_lock (in swap_duplicate, swap_info_get)
31 * mmlist_lock (in mmput, drain_mmlist and others)
32 * mapping->private_lock (in __set_page_dirty_buffers)
33 * inode->i_lock (in set_page_dirty's __mark_inode_dirty)
34 * bdi.wb->list_lock (in set_page_dirty's __mark_inode_dirty)
35 * sb_lock (within inode_lock in fs/fs-writeback.c)
36 * mapping->tree_lock (widely used, in set_page_dirty,
37 * in arch-dependent flush_dcache_mmap_lock,
38 * within bdi.wb->list_lock in __sync_single_inode)
40 * anon_vma->rwsem,mapping->i_mutex (memory_failure, collect_procs_anon)
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>
61 #include <asm/tlbflush.h>
65 static struct kmem_cache
*anon_vma_cachep
;
66 static struct kmem_cache
*anon_vma_chain_cachep
;
68 static inline struct anon_vma
*anon_vma_alloc(void)
70 struct anon_vma
*anon_vma
;
72 anon_vma
= kmem_cache_alloc(anon_vma_cachep
, GFP_KERNEL
);
74 atomic_set(&anon_vma
->refcount
, 1);
75 anon_vma
->degree
= 1; /* Reference for first vma */
76 anon_vma
->parent
= anon_vma
;
78 * Initialise the anon_vma root to point to itself. If called
79 * from fork, the root will be reset to the parents anon_vma.
81 anon_vma
->root
= anon_vma
;
87 static inline void anon_vma_free(struct anon_vma
*anon_vma
)
89 VM_BUG_ON(atomic_read(&anon_vma
->refcount
));
92 * Synchronize against page_lock_anon_vma_read() such that
93 * we can safely hold the lock without the anon_vma getting
96 * Relies on the full mb implied by the atomic_dec_and_test() from
97 * put_anon_vma() against the acquire barrier implied by
98 * down_read_trylock() from page_lock_anon_vma_read(). This orders:
100 * page_lock_anon_vma_read() VS put_anon_vma()
101 * down_read_trylock() atomic_dec_and_test()
103 * atomic_read() rwsem_is_locked()
105 * LOCK should suffice since the actual taking of the lock must
106 * happen _before_ what follows.
109 if (rwsem_is_locked(&anon_vma
->root
->rwsem
)) {
110 anon_vma_lock_write(anon_vma
);
111 anon_vma_unlock_write(anon_vma
);
114 kmem_cache_free(anon_vma_cachep
, anon_vma
);
117 static inline struct anon_vma_chain
*anon_vma_chain_alloc(gfp_t gfp
)
119 return kmem_cache_alloc(anon_vma_chain_cachep
, gfp
);
122 static void anon_vma_chain_free(struct anon_vma_chain
*anon_vma_chain
)
124 kmem_cache_free(anon_vma_chain_cachep
, anon_vma_chain
);
127 static void anon_vma_chain_link(struct vm_area_struct
*vma
,
128 struct anon_vma_chain
*avc
,
129 struct anon_vma
*anon_vma
)
132 avc
->anon_vma
= anon_vma
;
133 list_add(&avc
->same_vma
, &vma
->anon_vma_chain
);
134 anon_vma_interval_tree_insert(avc
, &anon_vma
->rb_root
);
138 * anon_vma_prepare - attach an anon_vma to a memory region
139 * @vma: the memory region in question
141 * This makes sure the memory mapping described by 'vma' has
142 * an 'anon_vma' attached to it, so that we can associate the
143 * anonymous pages mapped into it with that anon_vma.
145 * The common case will be that we already have one, but if
146 * not we either need to find an adjacent mapping that we
147 * can re-use the anon_vma from (very common when the only
148 * reason for splitting a vma has been mprotect()), or we
149 * allocate a new one.
151 * Anon-vma allocations are very subtle, because we may have
152 * optimistically looked up an anon_vma in page_lock_anon_vma_read()
153 * and that may actually touch the spinlock even in the newly
154 * allocated vma (it depends on RCU to make sure that the
155 * anon_vma isn't actually destroyed).
157 * As a result, we need to do proper anon_vma locking even
158 * for the new allocation. At the same time, we do not want
159 * to do any locking for the common case of already having
162 * This must be called with the mmap_sem held for reading.
164 int anon_vma_prepare(struct vm_area_struct
*vma
)
166 struct anon_vma
*anon_vma
= vma
->anon_vma
;
167 struct anon_vma_chain
*avc
;
170 if (unlikely(!anon_vma
)) {
171 struct mm_struct
*mm
= vma
->vm_mm
;
172 struct anon_vma
*allocated
;
174 avc
= anon_vma_chain_alloc(GFP_KERNEL
);
178 anon_vma
= find_mergeable_anon_vma(vma
);
181 anon_vma
= anon_vma_alloc();
182 if (unlikely(!anon_vma
))
183 goto out_enomem_free_avc
;
184 allocated
= anon_vma
;
187 anon_vma_lock_write(anon_vma
);
188 /* page_table_lock to protect against threads */
189 spin_lock(&mm
->page_table_lock
);
190 if (likely(!vma
->anon_vma
)) {
191 vma
->anon_vma
= anon_vma
;
192 anon_vma_chain_link(vma
, avc
, anon_vma
);
193 /* vma reference or self-parent link for new root */
198 spin_unlock(&mm
->page_table_lock
);
199 anon_vma_unlock_write(anon_vma
);
201 if (unlikely(allocated
))
202 put_anon_vma(allocated
);
204 anon_vma_chain_free(avc
);
209 anon_vma_chain_free(avc
);
215 * This is a useful helper function for locking the anon_vma root as
216 * we traverse the vma->anon_vma_chain, looping over anon_vma's that
219 * Such anon_vma's should have the same root, so you'd expect to see
220 * just a single mutex_lock for the whole traversal.
222 static inline struct anon_vma
*lock_anon_vma_root(struct anon_vma
*root
, struct anon_vma
*anon_vma
)
224 struct anon_vma
*new_root
= anon_vma
->root
;
225 if (new_root
!= root
) {
226 if (WARN_ON_ONCE(root
))
227 up_write(&root
->rwsem
);
229 down_write(&root
->rwsem
);
234 static inline void unlock_anon_vma_root(struct anon_vma
*root
)
237 up_write(&root
->rwsem
);
241 * Attach the anon_vmas from src to dst.
242 * Returns 0 on success, -ENOMEM on failure.
244 * If dst->anon_vma is NULL this function tries to find and reuse existing
245 * anon_vma which has no vmas and only one child anon_vma. This prevents
246 * degradation of anon_vma hierarchy to endless linear chain in case of
247 * constantly forking task. On the other hand, an anon_vma with more than one
248 * child isn't reused even if there was no alive vma, thus rmap walker has a
249 * good chance of avoiding scanning the whole hierarchy when it searches where
252 int anon_vma_clone(struct vm_area_struct
*dst
, struct vm_area_struct
*src
)
254 struct anon_vma_chain
*avc
, *pavc
;
255 struct anon_vma
*root
= NULL
;
257 list_for_each_entry_reverse(pavc
, &src
->anon_vma_chain
, same_vma
) {
258 struct anon_vma
*anon_vma
;
260 avc
= anon_vma_chain_alloc(GFP_NOWAIT
| __GFP_NOWARN
);
261 if (unlikely(!avc
)) {
262 unlock_anon_vma_root(root
);
264 avc
= anon_vma_chain_alloc(GFP_KERNEL
);
268 anon_vma
= pavc
->anon_vma
;
269 root
= lock_anon_vma_root(root
, anon_vma
);
270 anon_vma_chain_link(dst
, avc
, anon_vma
);
273 * Reuse existing anon_vma if its degree lower than two,
274 * that means it has no vma and only one anon_vma child.
276 * Do not chose parent anon_vma, otherwise first child
277 * will always reuse it. Root anon_vma is never reused:
278 * it has self-parent reference and at least one child.
280 if (!dst
->anon_vma
&& anon_vma
!= src
->anon_vma
&&
281 anon_vma
->degree
< 2)
282 dst
->anon_vma
= anon_vma
;
285 dst
->anon_vma
->degree
++;
286 unlock_anon_vma_root(root
);
290 unlink_anon_vmas(dst
);
295 * Attach vma to its own anon_vma, as well as to the anon_vmas that
296 * the corresponding VMA in the parent process is attached to.
297 * Returns 0 on success, non-zero on failure.
299 int anon_vma_fork(struct vm_area_struct
*vma
, struct vm_area_struct
*pvma
)
301 struct anon_vma_chain
*avc
;
302 struct anon_vma
*anon_vma
;
305 /* Don't bother if the parent process has no anon_vma here. */
309 /* Drop inherited anon_vma, we'll reuse existing or allocate new. */
310 vma
->anon_vma
= NULL
;
313 * First, attach the new VMA to the parent VMA's anon_vmas,
314 * so rmap can find non-COWed pages in child processes.
316 error
= anon_vma_clone(vma
, pvma
);
320 /* An existing anon_vma has been reused, all done then. */
324 /* Then add our own anon_vma. */
325 anon_vma
= anon_vma_alloc();
328 avc
= anon_vma_chain_alloc(GFP_KERNEL
);
330 goto out_error_free_anon_vma
;
333 * The root anon_vma's spinlock is the lock actually used when we
334 * lock any of the anon_vmas in this anon_vma tree.
336 anon_vma
->root
= pvma
->anon_vma
->root
;
337 anon_vma
->parent
= pvma
->anon_vma
;
339 * With refcounts, an anon_vma can stay around longer than the
340 * process it belongs to. The root anon_vma needs to be pinned until
341 * this anon_vma is freed, because the lock lives in the root.
343 get_anon_vma(anon_vma
->root
);
344 /* Mark this anon_vma as the one where our new (COWed) pages go. */
345 vma
->anon_vma
= anon_vma
;
346 anon_vma_lock_write(anon_vma
);
347 anon_vma_chain_link(vma
, avc
, anon_vma
);
348 anon_vma
->parent
->degree
++;
349 anon_vma_unlock_write(anon_vma
);
353 out_error_free_anon_vma
:
354 put_anon_vma(anon_vma
);
356 unlink_anon_vmas(vma
);
360 void unlink_anon_vmas(struct vm_area_struct
*vma
)
362 struct anon_vma_chain
*avc
, *next
;
363 struct anon_vma
*root
= NULL
;
366 * Unlink each anon_vma chained to the VMA. This list is ordered
367 * from newest to oldest, ensuring the root anon_vma gets freed last.
369 list_for_each_entry_safe(avc
, next
, &vma
->anon_vma_chain
, same_vma
) {
370 struct anon_vma
*anon_vma
= avc
->anon_vma
;
372 root
= lock_anon_vma_root(root
, anon_vma
);
373 anon_vma_interval_tree_remove(avc
, &anon_vma
->rb_root
);
376 * Leave empty anon_vmas on the list - we'll need
377 * to free them outside the lock.
379 if (RB_EMPTY_ROOT(&anon_vma
->rb_root
)) {
380 anon_vma
->parent
->degree
--;
384 list_del(&avc
->same_vma
);
385 anon_vma_chain_free(avc
);
388 vma
->anon_vma
->degree
--;
389 unlock_anon_vma_root(root
);
392 * Iterate the list once more, it now only contains empty and unlinked
393 * anon_vmas, destroy them. Could not do before due to __put_anon_vma()
394 * needing to write-acquire the anon_vma->root->rwsem.
396 list_for_each_entry_safe(avc
, next
, &vma
->anon_vma_chain
, same_vma
) {
397 struct anon_vma
*anon_vma
= avc
->anon_vma
;
399 BUG_ON(anon_vma
->degree
);
400 put_anon_vma(anon_vma
);
402 list_del(&avc
->same_vma
);
403 anon_vma_chain_free(avc
);
407 static void anon_vma_ctor(void *data
)
409 struct anon_vma
*anon_vma
= data
;
411 init_rwsem(&anon_vma
->rwsem
);
412 atomic_set(&anon_vma
->refcount
, 0);
413 anon_vma
->rb_root
= RB_ROOT
;
416 void __init
anon_vma_init(void)
418 anon_vma_cachep
= kmem_cache_create("anon_vma", sizeof(struct anon_vma
),
419 0, SLAB_DESTROY_BY_RCU
|SLAB_PANIC
, anon_vma_ctor
);
420 anon_vma_chain_cachep
= KMEM_CACHE(anon_vma_chain
, SLAB_PANIC
);
424 * Getting a lock on a stable anon_vma from a page off the LRU is tricky!
426 * Since there is no serialization what so ever against page_remove_rmap()
427 * the best this function can do is return a locked anon_vma that might
428 * have been relevant to this page.
430 * The page might have been remapped to a different anon_vma or the anon_vma
431 * returned may already be freed (and even reused).
433 * In case it was remapped to a different anon_vma, the new anon_vma will be a
434 * child of the old anon_vma, and the anon_vma lifetime rules will therefore
435 * ensure that any anon_vma obtained from the page will still be valid for as
436 * long as we observe page_mapped() [ hence all those page_mapped() tests ].
438 * All users of this function must be very careful when walking the anon_vma
439 * chain and verify that the page in question is indeed mapped in it
440 * [ something equivalent to page_mapped_in_vma() ].
442 * Since anon_vma's slab is DESTROY_BY_RCU and we know from page_remove_rmap()
443 * that the anon_vma pointer from page->mapping is valid if there is a
444 * mapcount, we can dereference the anon_vma after observing those.
446 struct anon_vma
*page_get_anon_vma(struct page
*page
)
448 struct anon_vma
*anon_vma
= NULL
;
449 unsigned long anon_mapping
;
452 anon_mapping
= (unsigned long) ACCESS_ONCE(page
->mapping
);
453 if ((anon_mapping
& PAGE_MAPPING_FLAGS
) != PAGE_MAPPING_ANON
)
455 if (!page_mapped(page
))
458 anon_vma
= (struct anon_vma
*) (anon_mapping
- PAGE_MAPPING_ANON
);
459 if (!atomic_inc_not_zero(&anon_vma
->refcount
)) {
465 * If this page is still mapped, then its anon_vma cannot have been
466 * freed. But if it has been unmapped, we have no security against the
467 * anon_vma structure being freed and reused (for another anon_vma:
468 * SLAB_DESTROY_BY_RCU guarantees that - so the atomic_inc_not_zero()
469 * above cannot corrupt).
471 if (!page_mapped(page
)) {
473 put_anon_vma(anon_vma
);
483 * Similar to page_get_anon_vma() except it locks the anon_vma.
485 * Its a little more complex as it tries to keep the fast path to a single
486 * atomic op -- the trylock. If we fail the trylock, we fall back to getting a
487 * reference like with page_get_anon_vma() and then block on the mutex.
489 struct anon_vma
*page_lock_anon_vma_read(struct page
*page
)
491 struct anon_vma
*anon_vma
= NULL
;
492 struct anon_vma
*root_anon_vma
;
493 unsigned long anon_mapping
;
496 anon_mapping
= (unsigned long) ACCESS_ONCE(page
->mapping
);
497 if ((anon_mapping
& PAGE_MAPPING_FLAGS
) != PAGE_MAPPING_ANON
)
499 if (!page_mapped(page
))
502 anon_vma
= (struct anon_vma
*) (anon_mapping
- PAGE_MAPPING_ANON
);
503 root_anon_vma
= ACCESS_ONCE(anon_vma
->root
);
504 if (down_read_trylock(&root_anon_vma
->rwsem
)) {
506 * If the page is still mapped, then this anon_vma is still
507 * its anon_vma, and holding the mutex ensures that it will
508 * not go away, see anon_vma_free().
510 if (!page_mapped(page
)) {
511 up_read(&root_anon_vma
->rwsem
);
517 /* trylock failed, we got to sleep */
518 if (!atomic_inc_not_zero(&anon_vma
->refcount
)) {
523 if (!page_mapped(page
)) {
525 put_anon_vma(anon_vma
);
529 /* we pinned the anon_vma, its safe to sleep */
531 anon_vma_lock_read(anon_vma
);
533 if (atomic_dec_and_test(&anon_vma
->refcount
)) {
535 * Oops, we held the last refcount, release the lock
536 * and bail -- can't simply use put_anon_vma() because
537 * we'll deadlock on the anon_vma_lock_write() recursion.
539 anon_vma_unlock_read(anon_vma
);
540 __put_anon_vma(anon_vma
);
551 void page_unlock_anon_vma_read(struct anon_vma
*anon_vma
)
553 anon_vma_unlock_read(anon_vma
);
557 * At what user virtual address is page expected in @vma?
559 static inline unsigned long
560 __vma_address(struct page
*page
, struct vm_area_struct
*vma
)
562 pgoff_t pgoff
= page_to_pgoff(page
);
563 return vma
->vm_start
+ ((pgoff
- vma
->vm_pgoff
) << PAGE_SHIFT
);
567 vma_address(struct page
*page
, struct vm_area_struct
*vma
)
569 unsigned long address
= __vma_address(page
, vma
);
571 /* page should be within @vma mapping range */
572 VM_BUG_ON_VMA(address
< vma
->vm_start
|| address
>= vma
->vm_end
, vma
);
578 * At what user virtual address is page expected in vma?
579 * Caller should check the page is actually part of the vma.
581 unsigned long page_address_in_vma(struct page
*page
, struct vm_area_struct
*vma
)
583 unsigned long address
;
584 if (PageAnon(page
)) {
585 struct anon_vma
*page__anon_vma
= page_anon_vma(page
);
587 * Note: swapoff's unuse_vma() is more efficient with this
588 * check, and needs it to match anon_vma when KSM is active.
590 if (!vma
->anon_vma
|| !page__anon_vma
||
591 vma
->anon_vma
->root
!= page__anon_vma
->root
)
593 } else if (page
->mapping
) {
594 if (!vma
->vm_file
|| vma
->vm_file
->f_mapping
!= page
->mapping
)
598 address
= __vma_address(page
, vma
);
599 if (unlikely(address
< vma
->vm_start
|| address
>= vma
->vm_end
))
604 pmd_t
*mm_find_pmd(struct mm_struct
*mm
, unsigned long address
)
611 pgd
= pgd_offset(mm
, address
);
612 if (!pgd_present(*pgd
))
615 pud
= pud_offset(pgd
, address
);
616 if (!pud_present(*pud
))
619 pmd
= pmd_offset(pud
, address
);
621 * Some THP functions use the sequence pmdp_clear_flush(), set_pmd_at()
622 * without holding anon_vma lock for write. So when looking for a
623 * genuine pmde (in which to find pte), test present and !THP together.
627 if (!pmd_present(pmde
) || pmd_trans_huge(pmde
))
634 * Check that @page is mapped at @address into @mm.
636 * If @sync is false, page_check_address may perform a racy check to avoid
637 * the page table lock when the pte is not present (helpful when reclaiming
638 * highly shared pages).
640 * On success returns with pte mapped and locked.
642 pte_t
*__page_check_address(struct page
*page
, struct mm_struct
*mm
,
643 unsigned long address
, spinlock_t
**ptlp
, int sync
)
649 if (unlikely(PageHuge(page
))) {
650 /* when pud is not present, pte will be NULL */
651 pte
= huge_pte_offset(mm
, address
);
655 ptl
= huge_pte_lockptr(page_hstate(page
), mm
, pte
);
659 pmd
= mm_find_pmd(mm
, address
);
663 pte
= pte_offset_map(pmd
, address
);
664 /* Make a quick check before getting the lock */
665 if (!sync
&& !pte_present(*pte
)) {
670 ptl
= pte_lockptr(mm
, pmd
);
673 if (pte_present(*pte
) && page_to_pfn(page
) == pte_pfn(*pte
)) {
677 pte_unmap_unlock(pte
, ptl
);
682 * page_mapped_in_vma - check whether a page is really mapped in a VMA
683 * @page: the page to test
684 * @vma: the VMA to test
686 * Returns 1 if the page is mapped into the page tables of the VMA, 0
687 * if the page is not mapped into the page tables of this VMA. Only
688 * valid for normal file or anonymous VMAs.
690 int page_mapped_in_vma(struct page
*page
, struct vm_area_struct
*vma
)
692 unsigned long address
;
696 address
= __vma_address(page
, vma
);
697 if (unlikely(address
< vma
->vm_start
|| address
>= vma
->vm_end
))
699 pte
= page_check_address(page
, vma
->vm_mm
, address
, &ptl
, 1);
700 if (!pte
) /* the page is not in this mm */
702 pte_unmap_unlock(pte
, ptl
);
707 struct page_referenced_arg
{
710 unsigned long vm_flags
;
711 struct mem_cgroup
*memcg
;
714 * arg: page_referenced_arg will be passed
716 static int page_referenced_one(struct page
*page
, struct vm_area_struct
*vma
,
717 unsigned long address
, void *arg
)
719 struct mm_struct
*mm
= vma
->vm_mm
;
722 struct page_referenced_arg
*pra
= arg
;
724 if (unlikely(PageTransHuge(page
))) {
728 * rmap might return false positives; we must filter
729 * these out using page_check_address_pmd().
731 pmd
= page_check_address_pmd(page
, mm
, address
,
732 PAGE_CHECK_ADDRESS_PMD_FLAG
, &ptl
);
736 if (vma
->vm_flags
& VM_LOCKED
) {
738 pra
->vm_flags
|= VM_LOCKED
;
739 return SWAP_FAIL
; /* To break the loop */
742 /* go ahead even if the pmd is pmd_trans_splitting() */
743 if (pmdp_clear_flush_young_notify(vma
, address
, pmd
))
750 * rmap might return false positives; we must filter
751 * these out using page_check_address().
753 pte
= page_check_address(page
, mm
, address
, &ptl
, 0);
757 if (vma
->vm_flags
& VM_LOCKED
) {
758 pte_unmap_unlock(pte
, ptl
);
759 pra
->vm_flags
|= VM_LOCKED
;
760 return SWAP_FAIL
; /* To break the loop */
763 if (ptep_clear_flush_young_notify(vma
, address
, pte
)) {
765 * Don't treat a reference through a sequentially read
766 * mapping as such. If the page has been used in
767 * another mapping, we will catch it; if this other
768 * mapping is already gone, the unmap path will have
769 * set PG_referenced or activated the page.
771 if (likely(!(vma
->vm_flags
& VM_SEQ_READ
)))
774 pte_unmap_unlock(pte
, ptl
);
779 pra
->vm_flags
|= vma
->vm_flags
;
784 return SWAP_SUCCESS
; /* To break the loop */
789 static bool invalid_page_referenced_vma(struct vm_area_struct
*vma
, void *arg
)
791 struct page_referenced_arg
*pra
= arg
;
792 struct mem_cgroup
*memcg
= pra
->memcg
;
794 if (!mm_match_cgroup(vma
->vm_mm
, memcg
))
801 * page_referenced - test if the page was referenced
802 * @page: the page to test
803 * @is_locked: caller holds lock on the page
804 * @memcg: target memory cgroup
805 * @vm_flags: collect encountered vma->vm_flags who actually referenced the page
807 * Quick test_and_clear_referenced for all mappings to a page,
808 * returns the number of ptes which referenced the page.
810 int page_referenced(struct page
*page
,
812 struct mem_cgroup
*memcg
,
813 unsigned long *vm_flags
)
817 struct page_referenced_arg pra
= {
818 .mapcount
= page_mapcount(page
),
821 struct rmap_walk_control rwc
= {
822 .rmap_one
= page_referenced_one
,
824 .anon_lock
= page_lock_anon_vma_read
,
828 if (!page_mapped(page
))
831 if (!page_rmapping(page
))
834 if (!is_locked
&& (!PageAnon(page
) || PageKsm(page
))) {
835 we_locked
= trylock_page(page
);
841 * If we are reclaiming on behalf of a cgroup, skip
842 * counting on behalf of references from different
846 rwc
.invalid_vma
= invalid_page_referenced_vma
;
849 ret
= rmap_walk(page
, &rwc
);
850 *vm_flags
= pra
.vm_flags
;
855 return pra
.referenced
;
858 static int page_mkclean_one(struct page
*page
, struct vm_area_struct
*vma
,
859 unsigned long address
, void *arg
)
861 struct mm_struct
*mm
= vma
->vm_mm
;
867 pte
= page_check_address(page
, mm
, address
, &ptl
, 1);
871 if (pte_dirty(*pte
) || pte_write(*pte
)) {
874 flush_cache_page(vma
, address
, pte_pfn(*pte
));
875 entry
= ptep_clear_flush(vma
, address
, pte
);
876 entry
= pte_wrprotect(entry
);
877 entry
= pte_mkclean(entry
);
878 set_pte_at(mm
, address
, pte
, entry
);
882 pte_unmap_unlock(pte
, ptl
);
885 mmu_notifier_invalidate_page(mm
, address
);
892 static bool invalid_mkclean_vma(struct vm_area_struct
*vma
, void *arg
)
894 if (vma
->vm_flags
& VM_SHARED
)
900 int page_mkclean(struct page
*page
)
903 struct address_space
*mapping
;
904 struct rmap_walk_control rwc
= {
905 .arg
= (void *)&cleaned
,
906 .rmap_one
= page_mkclean_one
,
907 .invalid_vma
= invalid_mkclean_vma
,
910 BUG_ON(!PageLocked(page
));
912 if (!page_mapped(page
))
915 mapping
= page_mapping(page
);
919 rmap_walk(page
, &rwc
);
923 EXPORT_SYMBOL_GPL(page_mkclean
);
926 * page_move_anon_rmap - move a page to our anon_vma
927 * @page: the page to move to our anon_vma
928 * @vma: the vma the page belongs to
929 * @address: the user virtual address mapped
931 * When a page belongs exclusively to one process after a COW event,
932 * that page can be moved into the anon_vma that belongs to just that
933 * process, so the rmap code will not search the parent or sibling
936 void page_move_anon_rmap(struct page
*page
,
937 struct vm_area_struct
*vma
, unsigned long address
)
939 struct anon_vma
*anon_vma
= vma
->anon_vma
;
941 VM_BUG_ON_PAGE(!PageLocked(page
), page
);
942 VM_BUG_ON_VMA(!anon_vma
, vma
);
943 VM_BUG_ON_PAGE(page
->index
!= linear_page_index(vma
, address
), page
);
945 anon_vma
= (void *) anon_vma
+ PAGE_MAPPING_ANON
;
946 page
->mapping
= (struct address_space
*) anon_vma
;
950 * __page_set_anon_rmap - set up new anonymous rmap
951 * @page: Page to add to rmap
952 * @vma: VM area to add page to.
953 * @address: User virtual address of the mapping
954 * @exclusive: the page is exclusively owned by the current process
956 static void __page_set_anon_rmap(struct page
*page
,
957 struct vm_area_struct
*vma
, unsigned long address
, int exclusive
)
959 struct anon_vma
*anon_vma
= vma
->anon_vma
;
967 * If the page isn't exclusively mapped into this vma,
968 * we must use the _oldest_ possible anon_vma for the
972 anon_vma
= anon_vma
->root
;
974 anon_vma
= (void *) anon_vma
+ PAGE_MAPPING_ANON
;
975 page
->mapping
= (struct address_space
*) anon_vma
;
976 page
->index
= linear_page_index(vma
, address
);
980 * __page_check_anon_rmap - sanity check anonymous rmap addition
981 * @page: the page to add the mapping to
982 * @vma: the vm area in which the mapping is added
983 * @address: the user virtual address mapped
985 static void __page_check_anon_rmap(struct page
*page
,
986 struct vm_area_struct
*vma
, unsigned long address
)
988 #ifdef CONFIG_DEBUG_VM
990 * The page's anon-rmap details (mapping and index) are guaranteed to
991 * be set up correctly at this point.
993 * We have exclusion against page_add_anon_rmap because the caller
994 * always holds the page locked, except if called from page_dup_rmap,
995 * in which case the page is already known to be setup.
997 * We have exclusion against page_add_new_anon_rmap because those pages
998 * are initially only visible via the pagetables, and the pte is locked
999 * over the call to page_add_new_anon_rmap.
1001 BUG_ON(page_anon_vma(page
)->root
!= vma
->anon_vma
->root
);
1002 BUG_ON(page
->index
!= linear_page_index(vma
, address
));
1007 * page_add_anon_rmap - add pte mapping to an anonymous page
1008 * @page: the page to add the mapping to
1009 * @vma: the vm area in which the mapping is added
1010 * @address: the user virtual address mapped
1012 * The caller needs to hold the pte lock, and the page must be locked in
1013 * the anon_vma case: to serialize mapping,index checking after setting,
1014 * and to ensure that PageAnon is not being upgraded racily to PageKsm
1015 * (but PageKsm is never downgraded to PageAnon).
1017 void page_add_anon_rmap(struct page
*page
,
1018 struct vm_area_struct
*vma
, unsigned long address
)
1020 do_page_add_anon_rmap(page
, vma
, address
, 0);
1024 * Special version of the above for do_swap_page, which often runs
1025 * into pages that are exclusively owned by the current process.
1026 * Everybody else should continue to use page_add_anon_rmap above.
1028 void do_page_add_anon_rmap(struct page
*page
,
1029 struct vm_area_struct
*vma
, unsigned long address
, int exclusive
)
1031 int first
= atomic_inc_and_test(&page
->_mapcount
);
1034 * We use the irq-unsafe __{inc|mod}_zone_page_stat because
1035 * these counters are not modified in interrupt context, and
1036 * pte lock(a spinlock) is held, which implies preemption
1039 if (PageTransHuge(page
))
1040 __inc_zone_page_state(page
,
1041 NR_ANON_TRANSPARENT_HUGEPAGES
);
1042 __mod_zone_page_state(page_zone(page
), NR_ANON_PAGES
,
1043 hpage_nr_pages(page
));
1045 if (unlikely(PageKsm(page
)))
1048 VM_BUG_ON_PAGE(!PageLocked(page
), page
);
1049 /* address might be in next vma when migration races vma_adjust */
1051 __page_set_anon_rmap(page
, vma
, address
, exclusive
);
1053 __page_check_anon_rmap(page
, vma
, address
);
1057 * page_add_new_anon_rmap - add pte mapping to a new anonymous page
1058 * @page: the page to add the mapping to
1059 * @vma: the vm area in which the mapping is added
1060 * @address: the user virtual address mapped
1062 * Same as page_add_anon_rmap but must only be called on *new* pages.
1063 * This means the inc-and-test can be bypassed.
1064 * Page does not have to be locked.
1066 void page_add_new_anon_rmap(struct page
*page
,
1067 struct vm_area_struct
*vma
, unsigned long address
)
1069 VM_BUG_ON_VMA(address
< vma
->vm_start
|| address
>= vma
->vm_end
, vma
);
1070 SetPageSwapBacked(page
);
1071 atomic_set(&page
->_mapcount
, 0); /* increment count (starts at -1) */
1072 if (PageTransHuge(page
))
1073 __inc_zone_page_state(page
, NR_ANON_TRANSPARENT_HUGEPAGES
);
1074 __mod_zone_page_state(page_zone(page
), NR_ANON_PAGES
,
1075 hpage_nr_pages(page
));
1076 __page_set_anon_rmap(page
, vma
, address
, 1);
1080 * page_add_file_rmap - add pte mapping to a file page
1081 * @page: the page to add the mapping to
1083 * The caller needs to hold the pte lock.
1085 void page_add_file_rmap(struct page
*page
)
1087 struct mem_cgroup
*memcg
;
1088 unsigned long flags
;
1091 memcg
= mem_cgroup_begin_page_stat(page
, &locked
, &flags
);
1092 if (atomic_inc_and_test(&page
->_mapcount
)) {
1093 __inc_zone_page_state(page
, NR_FILE_MAPPED
);
1094 mem_cgroup_inc_page_stat(memcg
, MEM_CGROUP_STAT_FILE_MAPPED
);
1096 mem_cgroup_end_page_stat(memcg
, &locked
, &flags
);
1099 static void page_remove_file_rmap(struct page
*page
)
1101 struct mem_cgroup
*memcg
;
1102 unsigned long flags
;
1105 memcg
= mem_cgroup_begin_page_stat(page
, &locked
, &flags
);
1107 /* page still mapped by someone else? */
1108 if (!atomic_add_negative(-1, &page
->_mapcount
))
1111 /* Hugepages are not counted in NR_FILE_MAPPED for now. */
1112 if (unlikely(PageHuge(page
)))
1116 * We use the irq-unsafe __{inc|mod}_zone_page_stat because
1117 * these counters are not modified in interrupt context, and
1118 * pte lock(a spinlock) is held, which implies preemption disabled.
1120 __dec_zone_page_state(page
, NR_FILE_MAPPED
);
1121 mem_cgroup_dec_page_stat(memcg
, MEM_CGROUP_STAT_FILE_MAPPED
);
1123 if (unlikely(PageMlocked(page
)))
1124 clear_page_mlock(page
);
1126 mem_cgroup_end_page_stat(memcg
, &locked
, &flags
);
1130 * page_remove_rmap - take down pte mapping from a page
1131 * @page: page to remove mapping from
1133 * The caller needs to hold the pte lock.
1135 void page_remove_rmap(struct page
*page
)
1137 if (!PageAnon(page
)) {
1138 page_remove_file_rmap(page
);
1142 /* page still mapped by someone else? */
1143 if (!atomic_add_negative(-1, &page
->_mapcount
))
1146 /* Hugepages are not counted in NR_ANON_PAGES for now. */
1147 if (unlikely(PageHuge(page
)))
1151 * We use the irq-unsafe __{inc|mod}_zone_page_stat because
1152 * these counters are not modified in interrupt context, and
1153 * pte lock(a spinlock) is held, which implies preemption disabled.
1155 if (PageTransHuge(page
))
1156 __dec_zone_page_state(page
, NR_ANON_TRANSPARENT_HUGEPAGES
);
1158 __mod_zone_page_state(page_zone(page
), NR_ANON_PAGES
,
1159 -hpage_nr_pages(page
));
1161 if (unlikely(PageMlocked(page
)))
1162 clear_page_mlock(page
);
1165 * It would be tidy to reset the PageAnon mapping here,
1166 * but that might overwrite a racing page_add_anon_rmap
1167 * which increments mapcount after us but sets mapping
1168 * before us: so leave the reset to free_hot_cold_page,
1169 * and remember that it's only reliable while mapped.
1170 * Leaving it set also helps swapoff to reinstate ptes
1171 * faster for those pages still in swapcache.
1176 * @arg: enum ttu_flags will be passed to this argument
1178 static int try_to_unmap_one(struct page
*page
, struct vm_area_struct
*vma
,
1179 unsigned long address
, void *arg
)
1181 struct mm_struct
*mm
= vma
->vm_mm
;
1185 int ret
= SWAP_AGAIN
;
1186 enum ttu_flags flags
= (enum ttu_flags
)arg
;
1188 pte
= page_check_address(page
, mm
, address
, &ptl
, 0);
1193 * If the page is mlock()d, we cannot swap it out.
1194 * If it's recently referenced (perhaps page_referenced
1195 * skipped over this mm) then we should reactivate it.
1197 if (!(flags
& TTU_IGNORE_MLOCK
)) {
1198 if (vma
->vm_flags
& VM_LOCKED
)
1201 if (flags
& TTU_MUNLOCK
)
1204 if (!(flags
& TTU_IGNORE_ACCESS
)) {
1205 if (ptep_clear_flush_young_notify(vma
, address
, pte
)) {
1211 /* Nuke the page table entry. */
1212 flush_cache_page(vma
, address
, page_to_pfn(page
));
1213 pteval
= ptep_clear_flush(vma
, address
, pte
);
1215 /* Move the dirty bit to the physical page now the pte is gone. */
1216 if (pte_dirty(pteval
))
1217 set_page_dirty(page
);
1219 /* Update high watermark before we lower rss */
1220 update_hiwater_rss(mm
);
1222 if (PageHWPoison(page
) && !(flags
& TTU_IGNORE_HWPOISON
)) {
1223 if (!PageHuge(page
)) {
1225 dec_mm_counter(mm
, MM_ANONPAGES
);
1227 dec_mm_counter(mm
, MM_FILEPAGES
);
1229 set_pte_at(mm
, address
, pte
,
1230 swp_entry_to_pte(make_hwpoison_entry(page
)));
1231 } else if (pte_unused(pteval
)) {
1233 * The guest indicated that the page content is of no
1234 * interest anymore. Simply discard the pte, vmscan
1235 * will take care of the rest.
1238 dec_mm_counter(mm
, MM_ANONPAGES
);
1240 dec_mm_counter(mm
, MM_FILEPAGES
);
1241 } else if (PageAnon(page
)) {
1242 swp_entry_t entry
= { .val
= page_private(page
) };
1245 if (PageSwapCache(page
)) {
1247 * Store the swap location in the pte.
1248 * See handle_pte_fault() ...
1250 if (swap_duplicate(entry
) < 0) {
1251 set_pte_at(mm
, address
, pte
, pteval
);
1255 if (list_empty(&mm
->mmlist
)) {
1256 spin_lock(&mmlist_lock
);
1257 if (list_empty(&mm
->mmlist
))
1258 list_add(&mm
->mmlist
, &init_mm
.mmlist
);
1259 spin_unlock(&mmlist_lock
);
1261 dec_mm_counter(mm
, MM_ANONPAGES
);
1262 inc_mm_counter(mm
, MM_SWAPENTS
);
1263 } else if (IS_ENABLED(CONFIG_MIGRATION
)) {
1265 * Store the pfn of the page in a special migration
1266 * pte. do_swap_page() will wait until the migration
1267 * pte is removed and then restart fault handling.
1269 BUG_ON(!(flags
& TTU_MIGRATION
));
1270 entry
= make_migration_entry(page
, pte_write(pteval
));
1272 swp_pte
= swp_entry_to_pte(entry
);
1273 if (pte_soft_dirty(pteval
))
1274 swp_pte
= pte_swp_mksoft_dirty(swp_pte
);
1275 set_pte_at(mm
, address
, pte
, swp_pte
);
1276 } else if (IS_ENABLED(CONFIG_MIGRATION
) &&
1277 (flags
& TTU_MIGRATION
)) {
1278 /* Establish migration entry for a file page */
1280 entry
= make_migration_entry(page
, pte_write(pteval
));
1281 set_pte_at(mm
, address
, pte
, swp_entry_to_pte(entry
));
1283 dec_mm_counter(mm
, MM_FILEPAGES
);
1285 page_remove_rmap(page
);
1286 page_cache_release(page
);
1289 pte_unmap_unlock(pte
, ptl
);
1290 if (ret
!= SWAP_FAIL
&& !(flags
& TTU_MUNLOCK
))
1291 mmu_notifier_invalidate_page(mm
, address
);
1296 pte_unmap_unlock(pte
, ptl
);
1300 * We need mmap_sem locking, Otherwise VM_LOCKED check makes
1301 * unstable result and race. Plus, We can't wait here because
1302 * we now hold anon_vma->rwsem or mapping->i_mmap_rwsem.
1303 * if trylock failed, the page remain in evictable lru and later
1304 * vmscan could retry to move the page to unevictable lru if the
1305 * page is actually mlocked.
1307 if (down_read_trylock(&vma
->vm_mm
->mmap_sem
)) {
1308 if (vma
->vm_flags
& VM_LOCKED
) {
1309 mlock_vma_page(page
);
1312 up_read(&vma
->vm_mm
->mmap_sem
);
1317 bool is_vma_temporary_stack(struct vm_area_struct
*vma
)
1319 int maybe_stack
= vma
->vm_flags
& (VM_GROWSDOWN
| VM_GROWSUP
);
1324 if ((vma
->vm_flags
& VM_STACK_INCOMPLETE_SETUP
) ==
1325 VM_STACK_INCOMPLETE_SETUP
)
1331 static bool invalid_migration_vma(struct vm_area_struct
*vma
, void *arg
)
1333 return is_vma_temporary_stack(vma
);
1336 static int page_not_mapped(struct page
*page
)
1338 return !page_mapped(page
);
1342 * try_to_unmap - try to remove all page table mappings to a page
1343 * @page: the page to get unmapped
1344 * @flags: action and flags
1346 * Tries to remove all the page table entries which are mapping this
1347 * page, used in the pageout path. Caller must hold the page lock.
1348 * Return values are:
1350 * SWAP_SUCCESS - we succeeded in removing all mappings
1351 * SWAP_AGAIN - we missed a mapping, try again later
1352 * SWAP_FAIL - the page is unswappable
1353 * SWAP_MLOCK - page is mlocked.
1355 int try_to_unmap(struct page
*page
, enum ttu_flags flags
)
1358 struct rmap_walk_control rwc
= {
1359 .rmap_one
= try_to_unmap_one
,
1360 .arg
= (void *)flags
,
1361 .done
= page_not_mapped
,
1362 .anon_lock
= page_lock_anon_vma_read
,
1365 VM_BUG_ON_PAGE(!PageHuge(page
) && PageTransHuge(page
), page
);
1368 * During exec, a temporary VMA is setup and later moved.
1369 * The VMA is moved under the anon_vma lock but not the
1370 * page tables leading to a race where migration cannot
1371 * find the migration ptes. Rather than increasing the
1372 * locking requirements of exec(), migration skips
1373 * temporary VMAs until after exec() completes.
1375 if ((flags
& TTU_MIGRATION
) && !PageKsm(page
) && PageAnon(page
))
1376 rwc
.invalid_vma
= invalid_migration_vma
;
1378 ret
= rmap_walk(page
, &rwc
);
1380 if (ret
!= SWAP_MLOCK
&& !page_mapped(page
))
1386 * try_to_munlock - try to munlock a page
1387 * @page: the page to be munlocked
1389 * Called from munlock code. Checks all of the VMAs mapping the page
1390 * to make sure nobody else has this page mlocked. The page will be
1391 * returned with PG_mlocked cleared if no other vmas have it mlocked.
1393 * Return values are:
1395 * SWAP_AGAIN - no vma is holding page mlocked, or,
1396 * SWAP_AGAIN - page mapped in mlocked vma -- couldn't acquire mmap sem
1397 * SWAP_FAIL - page cannot be located at present
1398 * SWAP_MLOCK - page is now mlocked.
1400 int try_to_munlock(struct page
*page
)
1403 struct rmap_walk_control rwc
= {
1404 .rmap_one
= try_to_unmap_one
,
1405 .arg
= (void *)TTU_MUNLOCK
,
1406 .done
= page_not_mapped
,
1407 .anon_lock
= page_lock_anon_vma_read
,
1411 VM_BUG_ON_PAGE(!PageLocked(page
) || PageLRU(page
), page
);
1413 ret
= rmap_walk(page
, &rwc
);
1417 void __put_anon_vma(struct anon_vma
*anon_vma
)
1419 struct anon_vma
*root
= anon_vma
->root
;
1421 anon_vma_free(anon_vma
);
1422 if (root
!= anon_vma
&& atomic_dec_and_test(&root
->refcount
))
1423 anon_vma_free(root
);
1426 static struct anon_vma
*rmap_walk_anon_lock(struct page
*page
,
1427 struct rmap_walk_control
*rwc
)
1429 struct anon_vma
*anon_vma
;
1432 return rwc
->anon_lock(page
);
1435 * Note: remove_migration_ptes() cannot use page_lock_anon_vma_read()
1436 * because that depends on page_mapped(); but not all its usages
1437 * are holding mmap_sem. Users without mmap_sem are required to
1438 * take a reference count to prevent the anon_vma disappearing
1440 anon_vma
= page_anon_vma(page
);
1444 anon_vma_lock_read(anon_vma
);
1449 * rmap_walk_anon - do something to anonymous page using the object-based
1451 * @page: the page to be handled
1452 * @rwc: control variable according to each walk type
1454 * Find all the mappings of a page using the mapping pointer and the vma chains
1455 * contained in the anon_vma struct it points to.
1457 * When called from try_to_munlock(), the mmap_sem of the mm containing the vma
1458 * where the page was found will be held for write. So, we won't recheck
1459 * vm_flags for that VMA. That should be OK, because that vma shouldn't be
1462 static int rmap_walk_anon(struct page
*page
, struct rmap_walk_control
*rwc
)
1464 struct anon_vma
*anon_vma
;
1466 struct anon_vma_chain
*avc
;
1467 int ret
= SWAP_AGAIN
;
1469 anon_vma
= rmap_walk_anon_lock(page
, rwc
);
1473 pgoff
= page_to_pgoff(page
);
1474 anon_vma_interval_tree_foreach(avc
, &anon_vma
->rb_root
, pgoff
, pgoff
) {
1475 struct vm_area_struct
*vma
= avc
->vma
;
1476 unsigned long address
= vma_address(page
, vma
);
1478 if (rwc
->invalid_vma
&& rwc
->invalid_vma(vma
, rwc
->arg
))
1481 ret
= rwc
->rmap_one(page
, vma
, address
, rwc
->arg
);
1482 if (ret
!= SWAP_AGAIN
)
1484 if (rwc
->done
&& rwc
->done(page
))
1487 anon_vma_unlock_read(anon_vma
);
1492 * rmap_walk_file - do something to file page using the object-based rmap method
1493 * @page: the page to be handled
1494 * @rwc: control variable according to each walk type
1496 * Find all the mappings of a page using the mapping pointer and the vma chains
1497 * contained in the address_space struct it points to.
1499 * When called from try_to_munlock(), the mmap_sem of the mm containing the vma
1500 * where the page was found will be held for write. So, we won't recheck
1501 * vm_flags for that VMA. That should be OK, because that vma shouldn't be
1504 static int rmap_walk_file(struct page
*page
, struct rmap_walk_control
*rwc
)
1506 struct address_space
*mapping
= page
->mapping
;
1508 struct vm_area_struct
*vma
;
1509 int ret
= SWAP_AGAIN
;
1512 * The page lock not only makes sure that page->mapping cannot
1513 * suddenly be NULLified by truncation, it makes sure that the
1514 * structure at mapping cannot be freed and reused yet,
1515 * so we can safely take mapping->i_mmap_rwsem.
1517 VM_BUG_ON_PAGE(!PageLocked(page
), page
);
1522 pgoff
= page_to_pgoff(page
);
1523 i_mmap_lock_read(mapping
);
1524 vma_interval_tree_foreach(vma
, &mapping
->i_mmap
, pgoff
, pgoff
) {
1525 unsigned long address
= vma_address(page
, vma
);
1527 if (rwc
->invalid_vma
&& rwc
->invalid_vma(vma
, rwc
->arg
))
1530 ret
= rwc
->rmap_one(page
, vma
, address
, rwc
->arg
);
1531 if (ret
!= SWAP_AGAIN
)
1533 if (rwc
->done
&& rwc
->done(page
))
1538 i_mmap_unlock_read(mapping
);
1542 int rmap_walk(struct page
*page
, struct rmap_walk_control
*rwc
)
1544 if (unlikely(PageKsm(page
)))
1545 return rmap_walk_ksm(page
, rwc
);
1546 else if (PageAnon(page
))
1547 return rmap_walk_anon(page
, rwc
);
1549 return rmap_walk_file(page
, rwc
);
1552 #ifdef CONFIG_HUGETLB_PAGE
1554 * The following three functions are for anonymous (private mapped) hugepages.
1555 * Unlike common anonymous pages, anonymous hugepages have no accounting code
1556 * and no lru code, because we handle hugepages differently from common pages.
1558 static void __hugepage_set_anon_rmap(struct page
*page
,
1559 struct vm_area_struct
*vma
, unsigned long address
, int exclusive
)
1561 struct anon_vma
*anon_vma
= vma
->anon_vma
;
1568 anon_vma
= anon_vma
->root
;
1570 anon_vma
= (void *) anon_vma
+ PAGE_MAPPING_ANON
;
1571 page
->mapping
= (struct address_space
*) anon_vma
;
1572 page
->index
= linear_page_index(vma
, address
);
1575 void hugepage_add_anon_rmap(struct page
*page
,
1576 struct vm_area_struct
*vma
, unsigned long address
)
1578 struct anon_vma
*anon_vma
= vma
->anon_vma
;
1581 BUG_ON(!PageLocked(page
));
1583 /* address might be in next vma when migration races vma_adjust */
1584 first
= atomic_inc_and_test(&page
->_mapcount
);
1586 __hugepage_set_anon_rmap(page
, vma
, address
, 0);
1589 void hugepage_add_new_anon_rmap(struct page
*page
,
1590 struct vm_area_struct
*vma
, unsigned long address
)
1592 BUG_ON(address
< vma
->vm_start
|| address
>= vma
->vm_end
);
1593 atomic_set(&page
->_mapcount
, 0);
1594 __hugepage_set_anon_rmap(page
, vma
, address
, 1);
1596 #endif /* CONFIG_HUGETLB_PAGE */