2 * Memory Migration functionality - linux/mm/migration.c
4 * Copyright (C) 2006 Silicon Graphics, Inc., Christoph Lameter
6 * Page migration was first developed in the context of the memory hotplug
7 * project. The main authors of the migration code are:
9 * IWAMOTO Toshihiro <iwamoto@valinux.co.jp>
10 * Hirokazu Takahashi <taka@valinux.co.jp>
11 * Dave Hansen <haveblue@us.ibm.com>
15 #include <linux/migrate.h>
16 #include <linux/export.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/ksm.h>
25 #include <linux/rmap.h>
26 #include <linux/topology.h>
27 #include <linux/cpu.h>
28 #include <linux/cpuset.h>
29 #include <linux/writeback.h>
30 #include <linux/mempolicy.h>
31 #include <linux/vmalloc.h>
32 #include <linux/security.h>
33 #include <linux/memcontrol.h>
34 #include <linux/syscalls.h>
35 #include <linux/hugetlb.h>
36 #include <linux/hugetlb_cgroup.h>
37 #include <linux/gfp.h>
38 #include <linux/balloon_compaction.h>
39 #include <linux/mmu_notifier.h>
41 #include <asm/tlbflush.h>
43 #define CREATE_TRACE_POINTS
44 #include <trace/events/migrate.h>
49 * migrate_prep() needs to be called before we start compiling a list of pages
50 * to be migrated using isolate_lru_page(). If scheduling work on other CPUs is
51 * undesirable, use migrate_prep_local()
53 int migrate_prep(void)
56 * Clear the LRU lists so pages can be isolated.
57 * Note that pages may be moved off the LRU after we have
58 * drained them. Those pages will fail to migrate like other
59 * pages that may be busy.
66 /* Do the necessary work of migrate_prep but not if it involves other CPUs */
67 int migrate_prep_local(void)
75 * Add isolated pages on the list back to the LRU under page lock
76 * to avoid leaking evictable pages back onto unevictable list.
78 void putback_lru_pages(struct list_head
*l
)
83 list_for_each_entry_safe(page
, page2
, l
, lru
) {
85 dec_zone_page_state(page
, NR_ISOLATED_ANON
+
86 page_is_file_cache(page
));
87 putback_lru_page(page
);
92 * Put previously isolated pages back onto the appropriate lists
93 * from where they were once taken off for compaction/migration.
95 * This function shall be used instead of putback_lru_pages(),
96 * whenever the isolated pageset has been built by isolate_migratepages_range()
98 void putback_movable_pages(struct list_head
*l
)
103 list_for_each_entry_safe(page
, page2
, l
, lru
) {
104 if (unlikely(PageHuge(page
))) {
105 putback_active_hugepage(page
);
108 list_del(&page
->lru
);
109 dec_zone_page_state(page
, NR_ISOLATED_ANON
+
110 page_is_file_cache(page
));
111 if (unlikely(isolated_balloon_page(page
)))
112 balloon_page_putback(page
);
114 putback_lru_page(page
);
119 * Restore a potential migration pte to a working pte entry
121 static int remove_migration_pte(struct page
*new, struct vm_area_struct
*vma
,
122 unsigned long addr
, void *old
)
124 struct mm_struct
*mm
= vma
->vm_mm
;
130 if (unlikely(PageHuge(new))) {
131 ptep
= huge_pte_offset(mm
, addr
);
134 ptl
= huge_pte_lockptr(hstate_vma(vma
), mm
, ptep
);
136 pmd
= mm_find_pmd(mm
, addr
);
139 if (pmd_trans_huge(*pmd
))
142 ptep
= pte_offset_map(pmd
, addr
);
145 * Peek to check is_swap_pte() before taking ptlock? No, we
146 * can race mremap's move_ptes(), which skips anon_vma lock.
149 ptl
= pte_lockptr(mm
, pmd
);
154 if (!is_swap_pte(pte
))
157 entry
= pte_to_swp_entry(pte
);
159 if (!is_migration_entry(entry
) ||
160 migration_entry_to_page(entry
) != old
)
164 pte
= pte_mkold(mk_pte(new, vma
->vm_page_prot
));
165 if (pte_swp_soft_dirty(*ptep
))
166 pte
= pte_mksoft_dirty(pte
);
167 if (is_write_migration_entry(entry
))
168 pte
= pte_mkwrite(pte
);
169 #ifdef CONFIG_HUGETLB_PAGE
171 pte
= pte_mkhuge(pte
);
172 pte
= arch_make_huge_pte(pte
, vma
, new, 0);
175 flush_dcache_page(new);
176 set_pte_at(mm
, addr
, ptep
, pte
);
180 hugepage_add_anon_rmap(new, vma
, addr
);
183 } else if (PageAnon(new))
184 page_add_anon_rmap(new, vma
, addr
);
186 page_add_file_rmap(new);
188 /* No need to invalidate - it was non-present before */
189 update_mmu_cache(vma
, addr
, ptep
);
191 pte_unmap_unlock(ptep
, ptl
);
197 * Get rid of all migration entries and replace them by
198 * references to the indicated page.
200 static void remove_migration_ptes(struct page
*old
, struct page
*new)
202 struct rmap_walk_control rwc
= {
203 .rmap_one
= remove_migration_pte
,
207 rmap_walk(new, &rwc
);
211 * Something used the pte of a page under migration. We need to
212 * get to the page and wait until migration is finished.
213 * When we return from this function the fault will be retried.
215 static void __migration_entry_wait(struct mm_struct
*mm
, pte_t
*ptep
,
224 if (!is_swap_pte(pte
))
227 entry
= pte_to_swp_entry(pte
);
228 if (!is_migration_entry(entry
))
231 page
= migration_entry_to_page(entry
);
234 * Once radix-tree replacement of page migration started, page_count
235 * *must* be zero. And, we don't want to call wait_on_page_locked()
236 * against a page without get_page().
237 * So, we use get_page_unless_zero(), here. Even failed, page fault
240 if (!get_page_unless_zero(page
))
242 pte_unmap_unlock(ptep
, ptl
);
243 wait_on_page_locked(page
);
247 pte_unmap_unlock(ptep
, ptl
);
250 void migration_entry_wait(struct mm_struct
*mm
, pmd_t
*pmd
,
251 unsigned long address
)
253 spinlock_t
*ptl
= pte_lockptr(mm
, pmd
);
254 pte_t
*ptep
= pte_offset_map(pmd
, address
);
255 __migration_entry_wait(mm
, ptep
, ptl
);
258 void migration_entry_wait_huge(struct vm_area_struct
*vma
,
259 struct mm_struct
*mm
, pte_t
*pte
)
261 spinlock_t
*ptl
= huge_pte_lockptr(hstate_vma(vma
), mm
, pte
);
262 __migration_entry_wait(mm
, pte
, ptl
);
266 /* Returns true if all buffers are successfully locked */
267 static bool buffer_migrate_lock_buffers(struct buffer_head
*head
,
268 enum migrate_mode mode
)
270 struct buffer_head
*bh
= head
;
272 /* Simple case, sync compaction */
273 if (mode
!= MIGRATE_ASYNC
) {
277 bh
= bh
->b_this_page
;
279 } while (bh
!= head
);
284 /* async case, we cannot block on lock_buffer so use trylock_buffer */
287 if (!trylock_buffer(bh
)) {
289 * We failed to lock the buffer and cannot stall in
290 * async migration. Release the taken locks
292 struct buffer_head
*failed_bh
= bh
;
295 while (bh
!= failed_bh
) {
298 bh
= bh
->b_this_page
;
303 bh
= bh
->b_this_page
;
304 } while (bh
!= head
);
308 static inline bool buffer_migrate_lock_buffers(struct buffer_head
*head
,
309 enum migrate_mode mode
)
313 #endif /* CONFIG_BLOCK */
316 * Replace the page in the mapping.
318 * The number of remaining references must be:
319 * 1 for anonymous pages without a mapping
320 * 2 for pages with a mapping
321 * 3 for pages with a mapping and PagePrivate/PagePrivate2 set.
323 int migrate_page_move_mapping(struct address_space
*mapping
,
324 struct page
*newpage
, struct page
*page
,
325 struct buffer_head
*head
, enum migrate_mode mode
,
328 int expected_count
= 1 + extra_count
;
332 /* Anonymous page without mapping */
333 if (page_count(page
) != expected_count
)
335 return MIGRATEPAGE_SUCCESS
;
338 spin_lock_irq(&mapping
->tree_lock
);
340 pslot
= radix_tree_lookup_slot(&mapping
->page_tree
,
343 expected_count
+= 1 + page_has_private(page
);
344 if (page_count(page
) != expected_count
||
345 radix_tree_deref_slot_protected(pslot
, &mapping
->tree_lock
) != page
) {
346 spin_unlock_irq(&mapping
->tree_lock
);
350 if (!page_freeze_refs(page
, expected_count
)) {
351 spin_unlock_irq(&mapping
->tree_lock
);
356 * In the async migration case of moving a page with buffers, lock the
357 * buffers using trylock before the mapping is moved. If the mapping
358 * was moved, we later failed to lock the buffers and could not move
359 * the mapping back due to an elevated page count, we would have to
360 * block waiting on other references to be dropped.
362 if (mode
== MIGRATE_ASYNC
&& head
&&
363 !buffer_migrate_lock_buffers(head
, mode
)) {
364 page_unfreeze_refs(page
, expected_count
);
365 spin_unlock_irq(&mapping
->tree_lock
);
370 * Now we know that no one else is looking at the page.
372 get_page(newpage
); /* add cache reference */
373 if (PageSwapCache(page
)) {
374 SetPageSwapCache(newpage
);
375 set_page_private(newpage
, page_private(page
));
378 radix_tree_replace_slot(pslot
, newpage
);
381 * Drop cache reference from old page by unfreezing
382 * to one less reference.
383 * We know this isn't the last reference.
385 page_unfreeze_refs(page
, expected_count
- 1);
388 * If moved to a different zone then also account
389 * the page for that zone. Other VM counters will be
390 * taken care of when we establish references to the
391 * new page and drop references to the old page.
393 * Note that anonymous pages are accounted for
394 * via NR_FILE_PAGES and NR_ANON_PAGES if they
395 * are mapped to swap space.
397 __dec_zone_page_state(page
, NR_FILE_PAGES
);
398 __inc_zone_page_state(newpage
, NR_FILE_PAGES
);
399 if (!PageSwapCache(page
) && PageSwapBacked(page
)) {
400 __dec_zone_page_state(page
, NR_SHMEM
);
401 __inc_zone_page_state(newpage
, NR_SHMEM
);
403 spin_unlock_irq(&mapping
->tree_lock
);
405 return MIGRATEPAGE_SUCCESS
;
409 * The expected number of remaining references is the same as that
410 * of migrate_page_move_mapping().
412 int migrate_huge_page_move_mapping(struct address_space
*mapping
,
413 struct page
*newpage
, struct page
*page
)
419 if (page_count(page
) != 1)
421 return MIGRATEPAGE_SUCCESS
;
424 spin_lock_irq(&mapping
->tree_lock
);
426 pslot
= radix_tree_lookup_slot(&mapping
->page_tree
,
429 expected_count
= 2 + page_has_private(page
);
430 if (page_count(page
) != expected_count
||
431 radix_tree_deref_slot_protected(pslot
, &mapping
->tree_lock
) != page
) {
432 spin_unlock_irq(&mapping
->tree_lock
);
436 if (!page_freeze_refs(page
, expected_count
)) {
437 spin_unlock_irq(&mapping
->tree_lock
);
443 radix_tree_replace_slot(pslot
, newpage
);
445 page_unfreeze_refs(page
, expected_count
- 1);
447 spin_unlock_irq(&mapping
->tree_lock
);
448 return MIGRATEPAGE_SUCCESS
;
452 * Gigantic pages are so large that we do not guarantee that page++ pointer
453 * arithmetic will work across the entire page. We need something more
456 static void __copy_gigantic_page(struct page
*dst
, struct page
*src
,
460 struct page
*dst_base
= dst
;
461 struct page
*src_base
= src
;
463 for (i
= 0; i
< nr_pages
; ) {
465 copy_highpage(dst
, src
);
468 dst
= mem_map_next(dst
, dst_base
, i
);
469 src
= mem_map_next(src
, src_base
, i
);
473 static void copy_huge_page(struct page
*dst
, struct page
*src
)
480 struct hstate
*h
= page_hstate(src
);
481 nr_pages
= pages_per_huge_page(h
);
483 if (unlikely(nr_pages
> MAX_ORDER_NR_PAGES
)) {
484 __copy_gigantic_page(dst
, src
, nr_pages
);
489 BUG_ON(!PageTransHuge(src
));
490 nr_pages
= hpage_nr_pages(src
);
493 for (i
= 0; i
< nr_pages
; i
++) {
495 copy_highpage(dst
+ i
, src
+ i
);
500 * Copy the page to its new location
502 void migrate_page_copy(struct page
*newpage
, struct page
*page
)
506 if (PageHuge(page
) || PageTransHuge(page
))
507 copy_huge_page(newpage
, page
);
509 copy_highpage(newpage
, page
);
512 SetPageError(newpage
);
513 if (PageReferenced(page
))
514 SetPageReferenced(newpage
);
515 if (PageUptodate(page
))
516 SetPageUptodate(newpage
);
517 if (TestClearPageActive(page
)) {
518 VM_BUG_ON(PageUnevictable(page
));
519 SetPageActive(newpage
);
520 } else if (TestClearPageUnevictable(page
))
521 SetPageUnevictable(newpage
);
522 if (PageChecked(page
))
523 SetPageChecked(newpage
);
524 if (PageMappedToDisk(page
))
525 SetPageMappedToDisk(newpage
);
527 if (PageDirty(page
)) {
528 clear_page_dirty_for_io(page
);
530 * Want to mark the page and the radix tree as dirty, and
531 * redo the accounting that clear_page_dirty_for_io undid,
532 * but we can't use set_page_dirty because that function
533 * is actually a signal that all of the page has become dirty.
534 * Whereas only part of our page may be dirty.
536 if (PageSwapBacked(page
))
537 SetPageDirty(newpage
);
539 __set_page_dirty_nobuffers(newpage
);
543 * Copy NUMA information to the new page, to prevent over-eager
544 * future migrations of this same page.
546 cpupid
= page_cpupid_xchg_last(page
, -1);
547 page_cpupid_xchg_last(newpage
, cpupid
);
549 mlock_migrate_page(newpage
, page
);
550 ksm_migrate_page(newpage
, page
);
552 * Please do not reorder this without considering how mm/ksm.c's
553 * get_ksm_page() depends upon ksm_migrate_page() and PageSwapCache().
555 ClearPageSwapCache(page
);
556 ClearPagePrivate(page
);
557 set_page_private(page
, 0);
560 * If any waiters have accumulated on the new page then
563 if (PageWriteback(newpage
))
564 end_page_writeback(newpage
);
567 /************************************************************
568 * Migration functions
569 ***********************************************************/
571 /* Always fail migration. Used for mappings that are not movable */
572 int fail_migrate_page(struct address_space
*mapping
,
573 struct page
*newpage
, struct page
*page
)
577 EXPORT_SYMBOL(fail_migrate_page
);
580 * Common logic to directly migrate a single page suitable for
581 * pages that do not use PagePrivate/PagePrivate2.
583 * Pages are locked upon entry and exit.
585 int migrate_page(struct address_space
*mapping
,
586 struct page
*newpage
, struct page
*page
,
587 enum migrate_mode mode
)
591 BUG_ON(PageWriteback(page
)); /* Writeback must be complete */
593 rc
= migrate_page_move_mapping(mapping
, newpage
, page
, NULL
, mode
, 0);
595 if (rc
!= MIGRATEPAGE_SUCCESS
)
598 migrate_page_copy(newpage
, page
);
599 return MIGRATEPAGE_SUCCESS
;
601 EXPORT_SYMBOL(migrate_page
);
605 * Migration function for pages with buffers. This function can only be used
606 * if the underlying filesystem guarantees that no other references to "page"
609 int buffer_migrate_page(struct address_space
*mapping
,
610 struct page
*newpage
, struct page
*page
, enum migrate_mode mode
)
612 struct buffer_head
*bh
, *head
;
615 if (!page_has_buffers(page
))
616 return migrate_page(mapping
, newpage
, page
, mode
);
618 head
= page_buffers(page
);
620 rc
= migrate_page_move_mapping(mapping
, newpage
, page
, head
, mode
, 0);
622 if (rc
!= MIGRATEPAGE_SUCCESS
)
626 * In the async case, migrate_page_move_mapping locked the buffers
627 * with an IRQ-safe spinlock held. In the sync case, the buffers
628 * need to be locked now
630 if (mode
!= MIGRATE_ASYNC
)
631 BUG_ON(!buffer_migrate_lock_buffers(head
, mode
));
633 ClearPagePrivate(page
);
634 set_page_private(newpage
, page_private(page
));
635 set_page_private(page
, 0);
641 set_bh_page(bh
, newpage
, bh_offset(bh
));
642 bh
= bh
->b_this_page
;
644 } while (bh
!= head
);
646 SetPagePrivate(newpage
);
648 migrate_page_copy(newpage
, page
);
654 bh
= bh
->b_this_page
;
656 } while (bh
!= head
);
658 return MIGRATEPAGE_SUCCESS
;
660 EXPORT_SYMBOL(buffer_migrate_page
);
664 * Writeback a page to clean the dirty state
666 static int writeout(struct address_space
*mapping
, struct page
*page
)
668 struct writeback_control wbc
= {
669 .sync_mode
= WB_SYNC_NONE
,
672 .range_end
= LLONG_MAX
,
677 if (!mapping
->a_ops
->writepage
)
678 /* No write method for the address space */
681 if (!clear_page_dirty_for_io(page
))
682 /* Someone else already triggered a write */
686 * A dirty page may imply that the underlying filesystem has
687 * the page on some queue. So the page must be clean for
688 * migration. Writeout may mean we loose the lock and the
689 * page state is no longer what we checked for earlier.
690 * At this point we know that the migration attempt cannot
693 remove_migration_ptes(page
, page
);
695 rc
= mapping
->a_ops
->writepage(page
, &wbc
);
697 if (rc
!= AOP_WRITEPAGE_ACTIVATE
)
698 /* unlocked. Relock */
701 return (rc
< 0) ? -EIO
: -EAGAIN
;
705 * Default handling if a filesystem does not provide a migration function.
707 static int fallback_migrate_page(struct address_space
*mapping
,
708 struct page
*newpage
, struct page
*page
, enum migrate_mode mode
)
710 if (PageDirty(page
)) {
711 /* Only writeback pages in full synchronous migration */
712 if (mode
!= MIGRATE_SYNC
)
714 return writeout(mapping
, page
);
718 * Buffers may be managed in a filesystem specific way.
719 * We must have no buffers or drop them.
721 if (page_has_private(page
) &&
722 !try_to_release_page(page
, GFP_KERNEL
))
725 return migrate_page(mapping
, newpage
, page
, mode
);
729 * Move a page to a newly allocated page
730 * The page is locked and all ptes have been successfully removed.
732 * The new page will have replaced the old page if this function
737 * MIGRATEPAGE_SUCCESS - success
739 static int move_to_new_page(struct page
*newpage
, struct page
*page
,
740 int remap_swapcache
, enum migrate_mode mode
)
742 struct address_space
*mapping
;
746 * Block others from accessing the page when we get around to
747 * establishing additional references. We are the only one
748 * holding a reference to the new page at this point.
750 if (!trylock_page(newpage
))
753 /* Prepare mapping for the new page.*/
754 newpage
->index
= page
->index
;
755 newpage
->mapping
= page
->mapping
;
756 if (PageSwapBacked(page
))
757 SetPageSwapBacked(newpage
);
759 mapping
= page_mapping(page
);
761 rc
= migrate_page(mapping
, newpage
, page
, mode
);
762 else if (mapping
->a_ops
->migratepage
)
764 * Most pages have a mapping and most filesystems provide a
765 * migratepage callback. Anonymous pages are part of swap
766 * space which also has its own migratepage callback. This
767 * is the most common path for page migration.
769 rc
= mapping
->a_ops
->migratepage(mapping
,
770 newpage
, page
, mode
);
772 rc
= fallback_migrate_page(mapping
, newpage
, page
, mode
);
774 if (rc
!= MIGRATEPAGE_SUCCESS
) {
775 newpage
->mapping
= NULL
;
778 remove_migration_ptes(page
, newpage
);
779 page
->mapping
= NULL
;
782 unlock_page(newpage
);
787 static int __unmap_and_move(struct page
*page
, struct page
*newpage
,
788 int force
, enum migrate_mode mode
)
791 int remap_swapcache
= 1;
792 struct mem_cgroup
*mem
;
793 struct anon_vma
*anon_vma
= NULL
;
795 if (!trylock_page(page
)) {
796 if (!force
|| mode
== MIGRATE_ASYNC
)
800 * It's not safe for direct compaction to call lock_page.
801 * For example, during page readahead pages are added locked
802 * to the LRU. Later, when the IO completes the pages are
803 * marked uptodate and unlocked. However, the queueing
804 * could be merging multiple pages for one bio (e.g.
805 * mpage_readpages). If an allocation happens for the
806 * second or third page, the process can end up locking
807 * the same page twice and deadlocking. Rather than
808 * trying to be clever about what pages can be locked,
809 * avoid the use of lock_page for direct compaction
812 if (current
->flags
& PF_MEMALLOC
)
818 /* charge against new page */
819 mem_cgroup_prepare_migration(page
, newpage
, &mem
);
821 if (PageWriteback(page
)) {
823 * Only in the case of a full synchronous migration is it
824 * necessary to wait for PageWriteback. In the async case,
825 * the retry loop is too short and in the sync-light case,
826 * the overhead of stalling is too much
828 if (mode
!= MIGRATE_SYNC
) {
834 wait_on_page_writeback(page
);
837 * By try_to_unmap(), page->mapcount goes down to 0 here. In this case,
838 * we cannot notice that anon_vma is freed while we migrates a page.
839 * This get_anon_vma() delays freeing anon_vma pointer until the end
840 * of migration. File cache pages are no problem because of page_lock()
841 * File Caches may use write_page() or lock_page() in migration, then,
842 * just care Anon page here.
844 if (PageAnon(page
) && !PageKsm(page
)) {
846 * Only page_lock_anon_vma_read() understands the subtleties of
847 * getting a hold on an anon_vma from outside one of its mms.
849 anon_vma
= page_get_anon_vma(page
);
854 } else if (PageSwapCache(page
)) {
856 * We cannot be sure that the anon_vma of an unmapped
857 * swapcache page is safe to use because we don't
858 * know in advance if the VMA that this page belonged
859 * to still exists. If the VMA and others sharing the
860 * data have been freed, then the anon_vma could
861 * already be invalid.
863 * To avoid this possibility, swapcache pages get
864 * migrated but are not remapped when migration
873 if (unlikely(balloon_page_movable(page
))) {
875 * A ballooned page does not need any special attention from
876 * physical to virtual reverse mapping procedures.
877 * Skip any attempt to unmap PTEs or to remap swap cache,
878 * in order to avoid burning cycles at rmap level, and perform
879 * the page migration right away (proteced by page lock).
881 rc
= balloon_page_migrate(newpage
, page
, mode
);
886 * Corner case handling:
887 * 1. When a new swap-cache page is read into, it is added to the LRU
888 * and treated as swapcache but it has no rmap yet.
889 * Calling try_to_unmap() against a page->mapping==NULL page will
890 * trigger a BUG. So handle it here.
891 * 2. An orphaned page (see truncate_complete_page) might have
892 * fs-private metadata. The page can be picked up due to memory
893 * offlining. Everywhere else except page reclaim, the page is
894 * invisible to the vm, so the page can not be migrated. So try to
895 * free the metadata, so the page can be freed.
897 if (!page
->mapping
) {
898 VM_BUG_ON(PageAnon(page
));
899 if (page_has_private(page
)) {
900 try_to_free_buffers(page
);
906 /* Establish migration ptes or remove ptes */
907 try_to_unmap(page
, TTU_MIGRATION
|TTU_IGNORE_MLOCK
|TTU_IGNORE_ACCESS
);
910 if (!page_mapped(page
))
911 rc
= move_to_new_page(newpage
, page
, remap_swapcache
, mode
);
913 if (rc
&& remap_swapcache
)
914 remove_migration_ptes(page
, page
);
916 /* Drop an anon_vma reference if we took one */
918 put_anon_vma(anon_vma
);
921 mem_cgroup_end_migration(mem
, page
, newpage
,
922 (rc
== MIGRATEPAGE_SUCCESS
||
923 rc
== MIGRATEPAGE_BALLOON_SUCCESS
));
930 * Obtain the lock on page, remove all ptes and migrate the page
931 * to the newly allocated page in newpage.
933 static int unmap_and_move(new_page_t get_new_page
, unsigned long private,
934 struct page
*page
, int force
, enum migrate_mode mode
)
938 struct page
*newpage
= get_new_page(page
, private, &result
);
943 if (page_count(page
) == 1) {
944 /* page was freed from under us. So we are done. */
948 if (unlikely(PageTransHuge(page
)))
949 if (unlikely(split_huge_page(page
)))
952 rc
= __unmap_and_move(page
, newpage
, force
, mode
);
954 if (unlikely(rc
== MIGRATEPAGE_BALLOON_SUCCESS
)) {
956 * A ballooned page has been migrated already.
957 * Now, it's the time to wrap-up counters,
958 * handle the page back to Buddy and return.
960 dec_zone_page_state(page
, NR_ISOLATED_ANON
+
961 page_is_file_cache(page
));
962 balloon_page_free(page
);
963 return MIGRATEPAGE_SUCCESS
;
968 * A page that has been migrated has all references
969 * removed and will be freed. A page that has not been
970 * migrated will have kepts its references and be
973 list_del(&page
->lru
);
974 dec_zone_page_state(page
, NR_ISOLATED_ANON
+
975 page_is_file_cache(page
));
976 putback_lru_page(page
);
979 * Move the new page to the LRU. If migration was not successful
980 * then this will free the page.
982 putback_lru_page(newpage
);
987 *result
= page_to_nid(newpage
);
993 * Counterpart of unmap_and_move_page() for hugepage migration.
995 * This function doesn't wait the completion of hugepage I/O
996 * because there is no race between I/O and migration for hugepage.
997 * Note that currently hugepage I/O occurs only in direct I/O
998 * where no lock is held and PG_writeback is irrelevant,
999 * and writeback status of all subpages are counted in the reference
1000 * count of the head page (i.e. if all subpages of a 2MB hugepage are
1001 * under direct I/O, the reference of the head page is 512 and a bit more.)
1002 * This means that when we try to migrate hugepage whose subpages are
1003 * doing direct I/O, some references remain after try_to_unmap() and
1004 * hugepage migration fails without data corruption.
1006 * There is also no race when direct I/O is issued on the page under migration,
1007 * because then pte is replaced with migration swap entry and direct I/O code
1008 * will wait in the page fault for migration to complete.
1010 static int unmap_and_move_huge_page(new_page_t get_new_page
,
1011 unsigned long private, struct page
*hpage
,
1012 int force
, enum migrate_mode mode
)
1016 struct page
*new_hpage
= get_new_page(hpage
, private, &result
);
1017 struct anon_vma
*anon_vma
= NULL
;
1020 * Movability of hugepages depends on architectures and hugepage size.
1021 * This check is necessary because some callers of hugepage migration
1022 * like soft offline and memory hotremove don't walk through page
1023 * tables or check whether the hugepage is pmd-based or not before
1024 * kicking migration.
1026 if (!hugepage_migration_support(page_hstate(hpage
)))
1034 if (!trylock_page(hpage
)) {
1035 if (!force
|| mode
!= MIGRATE_SYNC
)
1040 if (PageAnon(hpage
))
1041 anon_vma
= page_get_anon_vma(hpage
);
1043 try_to_unmap(hpage
, TTU_MIGRATION
|TTU_IGNORE_MLOCK
|TTU_IGNORE_ACCESS
);
1045 if (!page_mapped(hpage
))
1046 rc
= move_to_new_page(new_hpage
, hpage
, 1, mode
);
1049 remove_migration_ptes(hpage
, hpage
);
1052 put_anon_vma(anon_vma
);
1055 hugetlb_cgroup_migrate(hpage
, new_hpage
);
1060 putback_active_hugepage(hpage
);
1061 put_page(new_hpage
);
1066 *result
= page_to_nid(new_hpage
);
1072 * migrate_pages - migrate the pages specified in a list, to the free pages
1073 * supplied as the target for the page migration
1075 * @from: The list of pages to be migrated.
1076 * @get_new_page: The function used to allocate free pages to be used
1077 * as the target of the page migration.
1078 * @private: Private data to be passed on to get_new_page()
1079 * @mode: The migration mode that specifies the constraints for
1080 * page migration, if any.
1081 * @reason: The reason for page migration.
1083 * The function returns after 10 attempts or if no pages are movable any more
1084 * because the list has become empty or no retryable pages exist any more.
1085 * The caller should call putback_lru_pages() to return pages to the LRU
1086 * or free list only if ret != 0.
1088 * Returns the number of pages that were not migrated, or an error code.
1090 int migrate_pages(struct list_head
*from
, new_page_t get_new_page
,
1091 unsigned long private, enum migrate_mode mode
, int reason
)
1095 int nr_succeeded
= 0;
1099 int swapwrite
= current
->flags
& PF_SWAPWRITE
;
1103 current
->flags
|= PF_SWAPWRITE
;
1105 for(pass
= 0; pass
< 10 && retry
; pass
++) {
1108 list_for_each_entry_safe(page
, page2
, from
, lru
) {
1112 rc
= unmap_and_move_huge_page(get_new_page
,
1113 private, page
, pass
> 2, mode
);
1115 rc
= unmap_and_move(get_new_page
, private,
1116 page
, pass
> 2, mode
);
1124 case MIGRATEPAGE_SUCCESS
:
1128 /* Permanent failure */
1134 rc
= nr_failed
+ retry
;
1137 count_vm_events(PGMIGRATE_SUCCESS
, nr_succeeded
);
1139 count_vm_events(PGMIGRATE_FAIL
, nr_failed
);
1140 trace_mm_migrate_pages(nr_succeeded
, nr_failed
, mode
, reason
);
1143 current
->flags
&= ~PF_SWAPWRITE
;
1150 * Move a list of individual pages
1152 struct page_to_node
{
1159 static struct page
*new_page_node(struct page
*p
, unsigned long private,
1162 struct page_to_node
*pm
= (struct page_to_node
*)private;
1164 while (pm
->node
!= MAX_NUMNODES
&& pm
->page
!= p
)
1167 if (pm
->node
== MAX_NUMNODES
)
1170 *result
= &pm
->status
;
1173 return alloc_huge_page_node(page_hstate(compound_head(p
)),
1176 return alloc_pages_exact_node(pm
->node
,
1177 GFP_HIGHUSER_MOVABLE
| GFP_THISNODE
, 0);
1181 * Move a set of pages as indicated in the pm array. The addr
1182 * field must be set to the virtual address of the page to be moved
1183 * and the node number must contain a valid target node.
1184 * The pm array ends with node = MAX_NUMNODES.
1186 static int do_move_page_to_node_array(struct mm_struct
*mm
,
1187 struct page_to_node
*pm
,
1191 struct page_to_node
*pp
;
1192 LIST_HEAD(pagelist
);
1194 down_read(&mm
->mmap_sem
);
1197 * Build a list of pages to migrate
1199 for (pp
= pm
; pp
->node
!= MAX_NUMNODES
; pp
++) {
1200 struct vm_area_struct
*vma
;
1204 vma
= find_vma(mm
, pp
->addr
);
1205 if (!vma
|| pp
->addr
< vma
->vm_start
|| !vma_migratable(vma
))
1208 page
= follow_page(vma
, pp
->addr
, FOLL_GET
|FOLL_SPLIT
);
1210 err
= PTR_ERR(page
);
1218 /* Use PageReserved to check for zero page */
1219 if (PageReserved(page
))
1223 err
= page_to_nid(page
);
1225 if (err
== pp
->node
)
1227 * Node already in the right place
1232 if (page_mapcount(page
) > 1 &&
1236 if (PageHuge(page
)) {
1237 isolate_huge_page(page
, &pagelist
);
1241 err
= isolate_lru_page(page
);
1243 list_add_tail(&page
->lru
, &pagelist
);
1244 inc_zone_page_state(page
, NR_ISOLATED_ANON
+
1245 page_is_file_cache(page
));
1249 * Either remove the duplicate refcount from
1250 * isolate_lru_page() or drop the page ref if it was
1259 if (!list_empty(&pagelist
)) {
1260 err
= migrate_pages(&pagelist
, new_page_node
,
1261 (unsigned long)pm
, MIGRATE_SYNC
, MR_SYSCALL
);
1263 putback_movable_pages(&pagelist
);
1266 up_read(&mm
->mmap_sem
);
1271 * Migrate an array of page address onto an array of nodes and fill
1272 * the corresponding array of status.
1274 static int do_pages_move(struct mm_struct
*mm
, nodemask_t task_nodes
,
1275 unsigned long nr_pages
,
1276 const void __user
* __user
*pages
,
1277 const int __user
*nodes
,
1278 int __user
*status
, int flags
)
1280 struct page_to_node
*pm
;
1281 unsigned long chunk_nr_pages
;
1282 unsigned long chunk_start
;
1286 pm
= (struct page_to_node
*)__get_free_page(GFP_KERNEL
);
1293 * Store a chunk of page_to_node array in a page,
1294 * but keep the last one as a marker
1296 chunk_nr_pages
= (PAGE_SIZE
/ sizeof(struct page_to_node
)) - 1;
1298 for (chunk_start
= 0;
1299 chunk_start
< nr_pages
;
1300 chunk_start
+= chunk_nr_pages
) {
1303 if (chunk_start
+ chunk_nr_pages
> nr_pages
)
1304 chunk_nr_pages
= nr_pages
- chunk_start
;
1306 /* fill the chunk pm with addrs and nodes from user-space */
1307 for (j
= 0; j
< chunk_nr_pages
; j
++) {
1308 const void __user
*p
;
1312 if (get_user(p
, pages
+ j
+ chunk_start
))
1314 pm
[j
].addr
= (unsigned long) p
;
1316 if (get_user(node
, nodes
+ j
+ chunk_start
))
1320 if (node
< 0 || node
>= MAX_NUMNODES
)
1323 if (!node_state(node
, N_MEMORY
))
1327 if (!node_isset(node
, task_nodes
))
1333 /* End marker for this chunk */
1334 pm
[chunk_nr_pages
].node
= MAX_NUMNODES
;
1336 /* Migrate this chunk */
1337 err
= do_move_page_to_node_array(mm
, pm
,
1338 flags
& MPOL_MF_MOVE_ALL
);
1342 /* Return status information */
1343 for (j
= 0; j
< chunk_nr_pages
; j
++)
1344 if (put_user(pm
[j
].status
, status
+ j
+ chunk_start
)) {
1352 free_page((unsigned long)pm
);
1358 * Determine the nodes of an array of pages and store it in an array of status.
1360 static void do_pages_stat_array(struct mm_struct
*mm
, unsigned long nr_pages
,
1361 const void __user
**pages
, int *status
)
1365 down_read(&mm
->mmap_sem
);
1367 for (i
= 0; i
< nr_pages
; i
++) {
1368 unsigned long addr
= (unsigned long)(*pages
);
1369 struct vm_area_struct
*vma
;
1373 vma
= find_vma(mm
, addr
);
1374 if (!vma
|| addr
< vma
->vm_start
)
1377 page
= follow_page(vma
, addr
, 0);
1379 err
= PTR_ERR(page
);
1384 /* Use PageReserved to check for zero page */
1385 if (!page
|| PageReserved(page
))
1388 err
= page_to_nid(page
);
1396 up_read(&mm
->mmap_sem
);
1400 * Determine the nodes of a user array of pages and store it in
1401 * a user array of status.
1403 static int do_pages_stat(struct mm_struct
*mm
, unsigned long nr_pages
,
1404 const void __user
* __user
*pages
,
1407 #define DO_PAGES_STAT_CHUNK_NR 16
1408 const void __user
*chunk_pages
[DO_PAGES_STAT_CHUNK_NR
];
1409 int chunk_status
[DO_PAGES_STAT_CHUNK_NR
];
1412 unsigned long chunk_nr
;
1414 chunk_nr
= nr_pages
;
1415 if (chunk_nr
> DO_PAGES_STAT_CHUNK_NR
)
1416 chunk_nr
= DO_PAGES_STAT_CHUNK_NR
;
1418 if (copy_from_user(chunk_pages
, pages
, chunk_nr
* sizeof(*chunk_pages
)))
1421 do_pages_stat_array(mm
, chunk_nr
, chunk_pages
, chunk_status
);
1423 if (copy_to_user(status
, chunk_status
, chunk_nr
* sizeof(*status
)))
1428 nr_pages
-= chunk_nr
;
1430 return nr_pages
? -EFAULT
: 0;
1434 * Move a list of pages in the address space of the currently executing
1437 SYSCALL_DEFINE6(move_pages
, pid_t
, pid
, unsigned long, nr_pages
,
1438 const void __user
* __user
*, pages
,
1439 const int __user
*, nodes
,
1440 int __user
*, status
, int, flags
)
1442 const struct cred
*cred
= current_cred(), *tcred
;
1443 struct task_struct
*task
;
1444 struct mm_struct
*mm
;
1446 nodemask_t task_nodes
;
1449 if (flags
& ~(MPOL_MF_MOVE
|MPOL_MF_MOVE_ALL
))
1452 if ((flags
& MPOL_MF_MOVE_ALL
) && !capable(CAP_SYS_NICE
))
1455 /* Find the mm_struct */
1457 task
= pid
? find_task_by_vpid(pid
) : current
;
1462 get_task_struct(task
);
1465 * Check if this process has the right to modify the specified
1466 * process. The right exists if the process has administrative
1467 * capabilities, superuser privileges or the same
1468 * userid as the target process.
1470 tcred
= __task_cred(task
);
1471 if (!uid_eq(cred
->euid
, tcred
->suid
) && !uid_eq(cred
->euid
, tcred
->uid
) &&
1472 !uid_eq(cred
->uid
, tcred
->suid
) && !uid_eq(cred
->uid
, tcred
->uid
) &&
1473 !capable(CAP_SYS_NICE
)) {
1480 err
= security_task_movememory(task
);
1484 task_nodes
= cpuset_mems_allowed(task
);
1485 mm
= get_task_mm(task
);
1486 put_task_struct(task
);
1492 err
= do_pages_move(mm
, task_nodes
, nr_pages
, pages
,
1493 nodes
, status
, flags
);
1495 err
= do_pages_stat(mm
, nr_pages
, pages
, status
);
1501 put_task_struct(task
);
1506 * Call migration functions in the vma_ops that may prepare
1507 * memory in a vm for migration. migration functions may perform
1508 * the migration for vmas that do not have an underlying page struct.
1510 int migrate_vmas(struct mm_struct
*mm
, const nodemask_t
*to
,
1511 const nodemask_t
*from
, unsigned long flags
)
1513 struct vm_area_struct
*vma
;
1516 for (vma
= mm
->mmap
; vma
&& !err
; vma
= vma
->vm_next
) {
1517 if (vma
->vm_ops
&& vma
->vm_ops
->migrate
) {
1518 err
= vma
->vm_ops
->migrate(vma
, to
, from
, flags
);
1526 #ifdef CONFIG_NUMA_BALANCING
1528 * Returns true if this is a safe migration target node for misplaced NUMA
1529 * pages. Currently it only checks the watermarks which crude
1531 static bool migrate_balanced_pgdat(struct pglist_data
*pgdat
,
1532 unsigned long nr_migrate_pages
)
1535 for (z
= pgdat
->nr_zones
- 1; z
>= 0; z
--) {
1536 struct zone
*zone
= pgdat
->node_zones
+ z
;
1538 if (!populated_zone(zone
))
1541 if (!zone_reclaimable(zone
))
1544 /* Avoid waking kswapd by allocating pages_to_migrate pages. */
1545 if (!zone_watermark_ok(zone
, 0,
1546 high_wmark_pages(zone
) +
1555 static struct page
*alloc_misplaced_dst_page(struct page
*page
,
1559 int nid
= (int) data
;
1560 struct page
*newpage
;
1562 newpage
= alloc_pages_exact_node(nid
,
1563 (GFP_HIGHUSER_MOVABLE
| GFP_THISNODE
|
1564 __GFP_NOMEMALLOC
| __GFP_NORETRY
|
1568 page_cpupid_xchg_last(newpage
, page_cpupid_last(page
));
1574 * page migration rate limiting control.
1575 * Do not migrate more than @pages_to_migrate in a @migrate_interval_millisecs
1576 * window of time. Default here says do not migrate more than 1280M per second.
1577 * If a node is rate-limited then PTE NUMA updates are also rate-limited. However
1578 * as it is faults that reset the window, pte updates will happen unconditionally
1579 * if there has not been a fault since @pteupdate_interval_millisecs after the
1580 * throttle window closed.
1582 static unsigned int migrate_interval_millisecs __read_mostly
= 100;
1583 static unsigned int pteupdate_interval_millisecs __read_mostly
= 1000;
1584 static unsigned int ratelimit_pages __read_mostly
= 128 << (20 - PAGE_SHIFT
);
1586 /* Returns true if NUMA migration is currently rate limited */
1587 bool migrate_ratelimited(int node
)
1589 pg_data_t
*pgdat
= NODE_DATA(node
);
1591 if (time_after(jiffies
, pgdat
->numabalancing_migrate_next_window
+
1592 msecs_to_jiffies(pteupdate_interval_millisecs
)))
1595 if (pgdat
->numabalancing_migrate_nr_pages
< ratelimit_pages
)
1601 /* Returns true if the node is migrate rate-limited after the update */
1602 static bool numamigrate_update_ratelimit(pg_data_t
*pgdat
,
1603 unsigned long nr_pages
)
1606 * Rate-limit the amount of data that is being migrated to a node.
1607 * Optimal placement is no good if the memory bus is saturated and
1608 * all the time is being spent migrating!
1610 if (time_after(jiffies
, pgdat
->numabalancing_migrate_next_window
)) {
1611 spin_lock(&pgdat
->numabalancing_migrate_lock
);
1612 pgdat
->numabalancing_migrate_nr_pages
= 0;
1613 pgdat
->numabalancing_migrate_next_window
= jiffies
+
1614 msecs_to_jiffies(migrate_interval_millisecs
);
1615 spin_unlock(&pgdat
->numabalancing_migrate_lock
);
1617 if (pgdat
->numabalancing_migrate_nr_pages
> ratelimit_pages
) {
1618 trace_mm_numa_migrate_ratelimit(current
, pgdat
->node_id
,
1624 * This is an unlocked non-atomic update so errors are possible.
1625 * The consequences are failing to migrate when we potentiall should
1626 * have which is not severe enough to warrant locking. If it is ever
1627 * a problem, it can be converted to a per-cpu counter.
1629 pgdat
->numabalancing_migrate_nr_pages
+= nr_pages
;
1633 static int numamigrate_isolate_page(pg_data_t
*pgdat
, struct page
*page
)
1637 VM_BUG_ON(compound_order(page
) && !PageTransHuge(page
));
1639 /* Avoid migrating to a node that is nearly full */
1640 if (!migrate_balanced_pgdat(pgdat
, 1UL << compound_order(page
)))
1643 if (isolate_lru_page(page
))
1647 * migrate_misplaced_transhuge_page() skips page migration's usual
1648 * check on page_count(), so we must do it here, now that the page
1649 * has been isolated: a GUP pin, or any other pin, prevents migration.
1650 * The expected page count is 3: 1 for page's mapcount and 1 for the
1651 * caller's pin and 1 for the reference taken by isolate_lru_page().
1653 if (PageTransHuge(page
) && page_count(page
) != 3) {
1654 putback_lru_page(page
);
1658 page_lru
= page_is_file_cache(page
);
1659 mod_zone_page_state(page_zone(page
), NR_ISOLATED_ANON
+ page_lru
,
1660 hpage_nr_pages(page
));
1663 * Isolating the page has taken another reference, so the
1664 * caller's reference can be safely dropped without the page
1665 * disappearing underneath us during migration.
1671 bool pmd_trans_migrating(pmd_t pmd
)
1673 struct page
*page
= pmd_page(pmd
);
1674 return PageLocked(page
);
1677 void wait_migrate_huge_page(struct anon_vma
*anon_vma
, pmd_t
*pmd
)
1679 struct page
*page
= pmd_page(*pmd
);
1680 wait_on_page_locked(page
);
1684 * Attempt to migrate a misplaced page to the specified destination
1685 * node. Caller is expected to have an elevated reference count on
1686 * the page that will be dropped by this function before returning.
1688 int migrate_misplaced_page(struct page
*page
, struct vm_area_struct
*vma
,
1691 pg_data_t
*pgdat
= NODE_DATA(node
);
1694 LIST_HEAD(migratepages
);
1697 * Don't migrate file pages that are mapped in multiple processes
1698 * with execute permissions as they are probably shared libraries.
1700 if (page_mapcount(page
) != 1 && page_is_file_cache(page
) &&
1701 (vma
->vm_flags
& VM_EXEC
))
1705 * Rate-limit the amount of data that is being migrated to a node.
1706 * Optimal placement is no good if the memory bus is saturated and
1707 * all the time is being spent migrating!
1709 if (numamigrate_update_ratelimit(pgdat
, 1))
1712 isolated
= numamigrate_isolate_page(pgdat
, page
);
1716 list_add(&page
->lru
, &migratepages
);
1717 nr_remaining
= migrate_pages(&migratepages
, alloc_misplaced_dst_page
,
1718 node
, MIGRATE_ASYNC
, MR_NUMA_MISPLACED
);
1720 putback_lru_pages(&migratepages
);
1723 count_vm_numa_event(NUMA_PAGE_MIGRATE
);
1724 BUG_ON(!list_empty(&migratepages
));
1731 #endif /* CONFIG_NUMA_BALANCING */
1733 #if defined(CONFIG_NUMA_BALANCING) && defined(CONFIG_TRANSPARENT_HUGEPAGE)
1735 * Migrates a THP to a given target node. page must be locked and is unlocked
1738 int migrate_misplaced_transhuge_page(struct mm_struct
*mm
,
1739 struct vm_area_struct
*vma
,
1740 pmd_t
*pmd
, pmd_t entry
,
1741 unsigned long address
,
1742 struct page
*page
, int node
)
1745 pg_data_t
*pgdat
= NODE_DATA(node
);
1747 struct page
*new_page
= NULL
;
1748 struct mem_cgroup
*memcg
= NULL
;
1749 int page_lru
= page_is_file_cache(page
);
1750 unsigned long mmun_start
= address
& HPAGE_PMD_MASK
;
1751 unsigned long mmun_end
= mmun_start
+ HPAGE_PMD_SIZE
;
1755 * Rate-limit the amount of data that is being migrated to a node.
1756 * Optimal placement is no good if the memory bus is saturated and
1757 * all the time is being spent migrating!
1759 if (numamigrate_update_ratelimit(pgdat
, HPAGE_PMD_NR
))
1762 new_page
= alloc_pages_node(node
,
1763 (GFP_TRANSHUGE
| GFP_THISNODE
) & ~__GFP_WAIT
, HPAGE_PMD_ORDER
);
1767 page_cpupid_xchg_last(new_page
, page_cpupid_last(page
));
1769 isolated
= numamigrate_isolate_page(pgdat
, page
);
1775 if (mm_tlb_flush_pending(mm
))
1776 flush_tlb_range(vma
, mmun_start
, mmun_end
);
1778 /* Prepare a page as a migration target */
1779 __set_page_locked(new_page
);
1780 SetPageSwapBacked(new_page
);
1782 /* anon mapping, we can simply copy page->mapping to the new page: */
1783 new_page
->mapping
= page
->mapping
;
1784 new_page
->index
= page
->index
;
1785 migrate_page_copy(new_page
, page
);
1786 WARN_ON(PageLRU(new_page
));
1788 /* Recheck the target PMD */
1789 mmu_notifier_invalidate_range_start(mm
, mmun_start
, mmun_end
);
1790 ptl
= pmd_lock(mm
, pmd
);
1791 if (unlikely(!pmd_same(*pmd
, entry
) || page_count(page
) != 2)) {
1794 mmu_notifier_invalidate_range_end(mm
, mmun_start
, mmun_end
);
1796 /* Reverse changes made by migrate_page_copy() */
1797 if (TestClearPageActive(new_page
))
1798 SetPageActive(page
);
1799 if (TestClearPageUnevictable(new_page
))
1800 SetPageUnevictable(page
);
1801 mlock_migrate_page(page
, new_page
);
1803 unlock_page(new_page
);
1804 put_page(new_page
); /* Free it */
1806 /* Retake the callers reference and putback on LRU */
1808 putback_lru_page(page
);
1809 mod_zone_page_state(page_zone(page
),
1810 NR_ISOLATED_ANON
+ page_lru
, -HPAGE_PMD_NR
);
1816 * Traditional migration needs to prepare the memcg charge
1817 * transaction early to prevent the old page from being
1818 * uncharged when installing migration entries. Here we can
1819 * save the potential rollback and start the charge transfer
1820 * only when migration is already known to end successfully.
1822 mem_cgroup_prepare_migration(page
, new_page
, &memcg
);
1825 entry
= mk_pmd(new_page
, vma
->vm_page_prot
);
1826 entry
= pmd_mkhuge(entry
);
1827 entry
= maybe_pmd_mkwrite(pmd_mkdirty(entry
), vma
);
1830 * Clear the old entry under pagetable lock and establish the new PTE.
1831 * Any parallel GUP will either observe the old page blocking on the
1832 * page lock, block on the page table lock or observe the new page.
1833 * The SetPageUptodate on the new page and page_add_new_anon_rmap
1834 * guarantee the copy is visible before the pagetable update.
1836 flush_cache_range(vma
, mmun_start
, mmun_end
);
1837 page_add_new_anon_rmap(new_page
, vma
, mmun_start
);
1838 pmdp_clear_flush(vma
, mmun_start
, pmd
);
1839 set_pmd_at(mm
, mmun_start
, pmd
, entry
);
1840 flush_tlb_range(vma
, mmun_start
, mmun_end
);
1841 update_mmu_cache_pmd(vma
, address
, &entry
);
1843 if (page_count(page
) != 2) {
1844 set_pmd_at(mm
, mmun_start
, pmd
, orig_entry
);
1845 flush_tlb_range(vma
, mmun_start
, mmun_end
);
1846 update_mmu_cache_pmd(vma
, address
, &entry
);
1847 page_remove_rmap(new_page
);
1851 page_remove_rmap(page
);
1854 * Finish the charge transaction under the page table lock to
1855 * prevent split_huge_page() from dividing up the charge
1856 * before it's fully transferred to the new page.
1858 mem_cgroup_end_migration(memcg
, page
, new_page
, true);
1860 mmu_notifier_invalidate_range_end(mm
, mmun_start
, mmun_end
);
1862 unlock_page(new_page
);
1864 put_page(page
); /* Drop the rmap reference */
1865 put_page(page
); /* Drop the LRU isolation reference */
1867 count_vm_events(PGMIGRATE_SUCCESS
, HPAGE_PMD_NR
);
1868 count_vm_numa_events(NUMA_PAGE_MIGRATE
, HPAGE_PMD_NR
);
1870 mod_zone_page_state(page_zone(page
),
1871 NR_ISOLATED_ANON
+ page_lru
,
1876 count_vm_events(PGMIGRATE_FAIL
, HPAGE_PMD_NR
);
1878 ptl
= pmd_lock(mm
, pmd
);
1879 if (pmd_same(*pmd
, entry
)) {
1880 entry
= pmd_mknonnuma(entry
);
1881 set_pmd_at(mm
, mmun_start
, pmd
, entry
);
1882 update_mmu_cache_pmd(vma
, address
, &entry
);
1891 #endif /* CONFIG_NUMA_BALANCING */
1893 #endif /* CONFIG_NUMA */