]>
git.proxmox.com Git - mirror_ubuntu-jammy-kernel.git/blob - mm/migrate.c
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/module.h>
17 #include <linux/swap.h>
18 #include <linux/swapops.h>
19 #include <linux/pagemap.h>
20 #include <linux/buffer_head.h>
21 #include <linux/mm_inline.h>
22 #include <linux/nsproxy.h>
23 #include <linux/pagevec.h>
24 #include <linux/rmap.h>
25 #include <linux/topology.h>
26 #include <linux/cpu.h>
27 #include <linux/cpuset.h>
28 #include <linux/writeback.h>
29 #include <linux/mempolicy.h>
30 #include <linux/vmalloc.h>
31 #include <linux/security.h>
32 #include <linux/memcontrol.h>
33 #include <linux/syscalls.h>
37 #define lru_to_page(_head) (list_entry((_head)->prev, struct page, lru))
40 * migrate_prep() needs to be called before we start compiling a list of pages
41 * to be migrated using isolate_lru_page().
43 int migrate_prep(void)
46 * Clear the LRU lists so pages can be isolated.
47 * Note that pages may be moved off the LRU after we have
48 * drained them. Those pages will fail to migrate like other
49 * pages that may be busy.
57 * Add isolated pages on the list back to the LRU under page lock
58 * to avoid leaking evictable pages back onto unevictable list.
60 * returns the number of pages put back.
62 int putback_lru_pages(struct list_head
*l
)
68 list_for_each_entry_safe(page
, page2
, l
, lru
) {
70 dec_zone_page_state(page
, NR_ISOLATED_ANON
+
71 page_is_file_cache(page
));
72 putback_lru_page(page
);
79 * Restore a potential migration pte to a working pte entry
81 static void remove_migration_pte(struct vm_area_struct
*vma
,
82 struct page
*old
, struct page
*new)
84 struct mm_struct
*mm
= vma
->vm_mm
;
91 unsigned long addr
= page_address_in_vma(new, vma
);
96 pgd
= pgd_offset(mm
, addr
);
97 if (!pgd_present(*pgd
))
100 pud
= pud_offset(pgd
, addr
);
101 if (!pud_present(*pud
))
104 pmd
= pmd_offset(pud
, addr
);
105 if (!pmd_present(*pmd
))
108 ptep
= pte_offset_map(pmd
, addr
);
110 if (!is_swap_pte(*ptep
)) {
115 ptl
= pte_lockptr(mm
, pmd
);
118 if (!is_swap_pte(pte
))
121 entry
= pte_to_swp_entry(pte
);
123 if (!is_migration_entry(entry
) || migration_entry_to_page(entry
) != old
)
127 pte
= pte_mkold(mk_pte(new, vma
->vm_page_prot
));
128 if (is_write_migration_entry(entry
))
129 pte
= pte_mkwrite(pte
);
130 flush_cache_page(vma
, addr
, pte_pfn(pte
));
131 set_pte_at(mm
, addr
, ptep
, pte
);
134 page_add_anon_rmap(new, vma
, addr
);
136 page_add_file_rmap(new);
138 /* No need to invalidate - it was non-present before */
139 update_mmu_cache(vma
, addr
, pte
);
142 pte_unmap_unlock(ptep
, ptl
);
146 * Note that remove_file_migration_ptes will only work on regular mappings,
147 * Nonlinear mappings do not use migration entries.
149 static void remove_file_migration_ptes(struct page
*old
, struct page
*new)
151 struct vm_area_struct
*vma
;
152 struct address_space
*mapping
= new->mapping
;
153 struct prio_tree_iter iter
;
154 pgoff_t pgoff
= new->index
<< (PAGE_CACHE_SHIFT
- PAGE_SHIFT
);
159 spin_lock(&mapping
->i_mmap_lock
);
161 vma_prio_tree_foreach(vma
, &iter
, &mapping
->i_mmap
, pgoff
, pgoff
)
162 remove_migration_pte(vma
, old
, new);
164 spin_unlock(&mapping
->i_mmap_lock
);
168 * Must hold mmap_sem lock on at least one of the vmas containing
169 * the page so that the anon_vma cannot vanish.
171 static void remove_anon_migration_ptes(struct page
*old
, struct page
*new)
173 struct anon_vma
*anon_vma
;
174 struct vm_area_struct
*vma
;
175 unsigned long mapping
;
177 mapping
= (unsigned long)new->mapping
;
179 if (!mapping
|| (mapping
& PAGE_MAPPING_ANON
) == 0)
183 * We hold the mmap_sem lock. So no need to call page_lock_anon_vma.
185 anon_vma
= (struct anon_vma
*) (mapping
- PAGE_MAPPING_ANON
);
186 spin_lock(&anon_vma
->lock
);
188 list_for_each_entry(vma
, &anon_vma
->head
, anon_vma_node
)
189 remove_migration_pte(vma
, old
, new);
191 spin_unlock(&anon_vma
->lock
);
195 * Get rid of all migration entries and replace them by
196 * references to the indicated page.
198 static void remove_migration_ptes(struct page
*old
, struct page
*new)
201 remove_anon_migration_ptes(old
, new);
203 remove_file_migration_ptes(old
, new);
207 * Something used the pte of a page under migration. We need to
208 * get to the page and wait until migration is finished.
209 * When we return from this function the fault will be retried.
211 * This function is called from do_swap_page().
213 void migration_entry_wait(struct mm_struct
*mm
, pmd_t
*pmd
,
214 unsigned long address
)
221 ptep
= pte_offset_map_lock(mm
, pmd
, address
, &ptl
);
223 if (!is_swap_pte(pte
))
226 entry
= pte_to_swp_entry(pte
);
227 if (!is_migration_entry(entry
))
230 page
= migration_entry_to_page(entry
);
233 * Once radix-tree replacement of page migration started, page_count
234 * *must* be zero. And, we don't want to call wait_on_page_locked()
235 * against a page without get_page().
236 * So, we use get_page_unless_zero(), here. Even failed, page fault
239 if (!get_page_unless_zero(page
))
241 pte_unmap_unlock(ptep
, ptl
);
242 wait_on_page_locked(page
);
246 pte_unmap_unlock(ptep
, ptl
);
250 * Replace the page in the mapping.
252 * The number of remaining references must be:
253 * 1 for anonymous pages without a mapping
254 * 2 for pages with a mapping
255 * 3 for pages with a mapping and PagePrivate/PagePrivate2 set.
257 static int migrate_page_move_mapping(struct address_space
*mapping
,
258 struct page
*newpage
, struct page
*page
)
264 /* Anonymous page without mapping */
265 if (page_count(page
) != 1)
270 spin_lock_irq(&mapping
->tree_lock
);
272 pslot
= radix_tree_lookup_slot(&mapping
->page_tree
,
275 expected_count
= 2 + page_has_private(page
);
276 if (page_count(page
) != expected_count
||
277 (struct page
*)radix_tree_deref_slot(pslot
) != page
) {
278 spin_unlock_irq(&mapping
->tree_lock
);
282 if (!page_freeze_refs(page
, expected_count
)) {
283 spin_unlock_irq(&mapping
->tree_lock
);
288 * Now we know that no one else is looking at the page.
290 get_page(newpage
); /* add cache reference */
291 if (PageSwapCache(page
)) {
292 SetPageSwapCache(newpage
);
293 set_page_private(newpage
, page_private(page
));
296 radix_tree_replace_slot(pslot
, newpage
);
298 page_unfreeze_refs(page
, expected_count
);
300 * Drop cache reference from old page.
301 * We know this isn't the last reference.
306 * If moved to a different zone then also account
307 * the page for that zone. Other VM counters will be
308 * taken care of when we establish references to the
309 * new page and drop references to the old page.
311 * Note that anonymous pages are accounted for
312 * via NR_FILE_PAGES and NR_ANON_PAGES if they
313 * are mapped to swap space.
315 __dec_zone_page_state(page
, NR_FILE_PAGES
);
316 __inc_zone_page_state(newpage
, NR_FILE_PAGES
);
317 if (PageSwapBacked(page
)) {
318 __dec_zone_page_state(page
, NR_SHMEM
);
319 __inc_zone_page_state(newpage
, NR_SHMEM
);
321 spin_unlock_irq(&mapping
->tree_lock
);
327 * Copy the page to its new location
329 static void migrate_page_copy(struct page
*newpage
, struct page
*page
)
333 copy_highpage(newpage
, page
);
336 SetPageError(newpage
);
337 if (PageReferenced(page
))
338 SetPageReferenced(newpage
);
339 if (PageUptodate(page
))
340 SetPageUptodate(newpage
);
341 if (TestClearPageActive(page
)) {
342 VM_BUG_ON(PageUnevictable(page
));
343 SetPageActive(newpage
);
345 unevictable_migrate_page(newpage
, page
);
346 if (PageChecked(page
))
347 SetPageChecked(newpage
);
348 if (PageMappedToDisk(page
))
349 SetPageMappedToDisk(newpage
);
351 if (PageDirty(page
)) {
352 clear_page_dirty_for_io(page
);
354 * Want to mark the page and the radix tree as dirty, and
355 * redo the accounting that clear_page_dirty_for_io undid,
356 * but we can't use set_page_dirty because that function
357 * is actually a signal that all of the page has become dirty.
358 * Wheras only part of our page may be dirty.
360 __set_page_dirty_nobuffers(newpage
);
363 mlock_migrate_page(newpage
, page
);
365 ClearPageSwapCache(page
);
366 ClearPagePrivate(page
);
367 set_page_private(page
, 0);
368 /* page->mapping contains a flag for PageAnon() */
369 anon
= PageAnon(page
);
370 page
->mapping
= NULL
;
373 * If any waiters have accumulated on the new page then
376 if (PageWriteback(newpage
))
377 end_page_writeback(newpage
);
380 /************************************************************
381 * Migration functions
382 ***********************************************************/
384 /* Always fail migration. Used for mappings that are not movable */
385 int fail_migrate_page(struct address_space
*mapping
,
386 struct page
*newpage
, struct page
*page
)
390 EXPORT_SYMBOL(fail_migrate_page
);
393 * Common logic to directly migrate a single page suitable for
394 * pages that do not use PagePrivate/PagePrivate2.
396 * Pages are locked upon entry and exit.
398 int migrate_page(struct address_space
*mapping
,
399 struct page
*newpage
, struct page
*page
)
403 BUG_ON(PageWriteback(page
)); /* Writeback must be complete */
405 rc
= migrate_page_move_mapping(mapping
, newpage
, page
);
410 migrate_page_copy(newpage
, page
);
413 EXPORT_SYMBOL(migrate_page
);
417 * Migration function for pages with buffers. This function can only be used
418 * if the underlying filesystem guarantees that no other references to "page"
421 int buffer_migrate_page(struct address_space
*mapping
,
422 struct page
*newpage
, struct page
*page
)
424 struct buffer_head
*bh
, *head
;
427 if (!page_has_buffers(page
))
428 return migrate_page(mapping
, newpage
, page
);
430 head
= page_buffers(page
);
432 rc
= migrate_page_move_mapping(mapping
, newpage
, page
);
441 bh
= bh
->b_this_page
;
443 } while (bh
!= head
);
445 ClearPagePrivate(page
);
446 set_page_private(newpage
, page_private(page
));
447 set_page_private(page
, 0);
453 set_bh_page(bh
, newpage
, bh_offset(bh
));
454 bh
= bh
->b_this_page
;
456 } while (bh
!= head
);
458 SetPagePrivate(newpage
);
460 migrate_page_copy(newpage
, page
);
466 bh
= bh
->b_this_page
;
468 } while (bh
!= head
);
472 EXPORT_SYMBOL(buffer_migrate_page
);
476 * Writeback a page to clean the dirty state
478 static int writeout(struct address_space
*mapping
, struct page
*page
)
480 struct writeback_control wbc
= {
481 .sync_mode
= WB_SYNC_NONE
,
484 .range_end
= LLONG_MAX
,
490 if (!mapping
->a_ops
->writepage
)
491 /* No write method for the address space */
494 if (!clear_page_dirty_for_io(page
))
495 /* Someone else already triggered a write */
499 * A dirty page may imply that the underlying filesystem has
500 * the page on some queue. So the page must be clean for
501 * migration. Writeout may mean we loose the lock and the
502 * page state is no longer what we checked for earlier.
503 * At this point we know that the migration attempt cannot
506 remove_migration_ptes(page
, page
);
508 rc
= mapping
->a_ops
->writepage(page
, &wbc
);
510 if (rc
!= AOP_WRITEPAGE_ACTIVATE
)
511 /* unlocked. Relock */
514 return (rc
< 0) ? -EIO
: -EAGAIN
;
518 * Default handling if a filesystem does not provide a migration function.
520 static int fallback_migrate_page(struct address_space
*mapping
,
521 struct page
*newpage
, struct page
*page
)
524 return writeout(mapping
, page
);
527 * Buffers may be managed in a filesystem specific way.
528 * We must have no buffers or drop them.
530 if (page_has_private(page
) &&
531 !try_to_release_page(page
, GFP_KERNEL
))
534 return migrate_page(mapping
, newpage
, page
);
538 * Move a page to a newly allocated page
539 * The page is locked and all ptes have been successfully removed.
541 * The new page will have replaced the old page if this function
548 static int move_to_new_page(struct page
*newpage
, struct page
*page
)
550 struct address_space
*mapping
;
554 * Block others from accessing the page when we get around to
555 * establishing additional references. We are the only one
556 * holding a reference to the new page at this point.
558 if (!trylock_page(newpage
))
561 /* Prepare mapping for the new page.*/
562 newpage
->index
= page
->index
;
563 newpage
->mapping
= page
->mapping
;
564 if (PageSwapBacked(page
))
565 SetPageSwapBacked(newpage
);
567 mapping
= page_mapping(page
);
569 rc
= migrate_page(mapping
, newpage
, page
);
570 else if (mapping
->a_ops
->migratepage
)
572 * Most pages have a mapping and most filesystems
573 * should provide a migration function. Anonymous
574 * pages are part of swap space which also has its
575 * own migration function. This is the most common
576 * path for page migration.
578 rc
= mapping
->a_ops
->migratepage(mapping
,
581 rc
= fallback_migrate_page(mapping
, newpage
, page
);
584 remove_migration_ptes(page
, newpage
);
586 newpage
->mapping
= NULL
;
588 unlock_page(newpage
);
594 * Obtain the lock on page, remove all ptes and migrate the page
595 * to the newly allocated page in newpage.
597 static int unmap_and_move(new_page_t get_new_page
, unsigned long private,
598 struct page
*page
, int force
)
602 struct page
*newpage
= get_new_page(page
, private, &result
);
605 struct mem_cgroup
*mem
= NULL
;
610 if (page_count(page
) == 1) {
611 /* page was freed from under us. So we are done. */
615 /* prepare cgroup just returns 0 or -ENOMEM */
618 if (!trylock_page(page
)) {
624 /* charge against new page */
625 charge
= mem_cgroup_prepare_migration(page
, &mem
);
626 if (charge
== -ENOMEM
) {
632 if (PageWriteback(page
)) {
635 wait_on_page_writeback(page
);
638 * By try_to_unmap(), page->mapcount goes down to 0 here. In this case,
639 * we cannot notice that anon_vma is freed while we migrates a page.
640 * This rcu_read_lock() delays freeing anon_vma pointer until the end
641 * of migration. File cache pages are no problem because of page_lock()
642 * File Caches may use write_page() or lock_page() in migration, then,
643 * just care Anon page here.
645 if (PageAnon(page
)) {
651 * Corner case handling:
652 * 1. When a new swap-cache page is read into, it is added to the LRU
653 * and treated as swapcache but it has no rmap yet.
654 * Calling try_to_unmap() against a page->mapping==NULL page will
655 * trigger a BUG. So handle it here.
656 * 2. An orphaned page (see truncate_complete_page) might have
657 * fs-private metadata. The page can be picked up due to memory
658 * offlining. Everywhere else except page reclaim, the page is
659 * invisible to the vm, so the page can not be migrated. So try to
660 * free the metadata, so the page can be freed.
662 if (!page
->mapping
) {
663 if (!PageAnon(page
) && page_has_private(page
)) {
665 * Go direct to try_to_free_buffers() here because
666 * a) that's what try_to_release_page() would do anyway
667 * b) we may be under rcu_read_lock() here, so we can't
668 * use GFP_KERNEL which is what try_to_release_page()
669 * needs to be effective.
671 try_to_free_buffers(page
);
677 /* Establish migration ptes or remove ptes */
678 try_to_unmap(page
, TTU_MIGRATION
|TTU_IGNORE_MLOCK
|TTU_IGNORE_ACCESS
);
681 if (!page_mapped(page
))
682 rc
= move_to_new_page(newpage
, page
);
685 remove_migration_ptes(page
, page
);
691 mem_cgroup_end_migration(mem
, page
, newpage
);
697 * A page that has been migrated has all references
698 * removed and will be freed. A page that has not been
699 * migrated will have kepts its references and be
702 list_del(&page
->lru
);
703 dec_zone_page_state(page
, NR_ISOLATED_ANON
+
704 page_is_file_cache(page
));
705 putback_lru_page(page
);
711 * Move the new page to the LRU. If migration was not successful
712 * then this will free the page.
714 putback_lru_page(newpage
);
720 *result
= page_to_nid(newpage
);
728 * The function takes one list of pages to migrate and a function
729 * that determines from the page to be migrated and the private data
730 * the target of the move and allocates the page.
732 * The function returns after 10 attempts or if no pages
733 * are movable anymore because to has become empty
734 * or no retryable pages exist anymore. All pages will be
735 * returned to the LRU or freed.
737 * Return: Number of pages not migrated or error code.
739 int migrate_pages(struct list_head
*from
,
740 new_page_t get_new_page
, unsigned long private)
747 int swapwrite
= current
->flags
& PF_SWAPWRITE
;
751 local_irq_save(flags
);
752 list_for_each_entry(page
, from
, lru
)
753 __inc_zone_page_state(page
, NR_ISOLATED_ANON
+
754 page_is_file_cache(page
));
755 local_irq_restore(flags
);
758 current
->flags
|= PF_SWAPWRITE
;
760 for(pass
= 0; pass
< 10 && retry
; pass
++) {
763 list_for_each_entry_safe(page
, page2
, from
, lru
) {
766 rc
= unmap_and_move(get_new_page
, private,
778 /* Permanent failure */
787 current
->flags
&= ~PF_SWAPWRITE
;
789 putback_lru_pages(from
);
794 return nr_failed
+ retry
;
799 * Move a list of individual pages
801 struct page_to_node
{
808 static struct page
*new_page_node(struct page
*p
, unsigned long private,
811 struct page_to_node
*pm
= (struct page_to_node
*)private;
813 while (pm
->node
!= MAX_NUMNODES
&& pm
->page
!= p
)
816 if (pm
->node
== MAX_NUMNODES
)
819 *result
= &pm
->status
;
821 return alloc_pages_exact_node(pm
->node
,
822 GFP_HIGHUSER_MOVABLE
| GFP_THISNODE
, 0);
826 * Move a set of pages as indicated in the pm array. The addr
827 * field must be set to the virtual address of the page to be moved
828 * and the node number must contain a valid target node.
829 * The pm array ends with node = MAX_NUMNODES.
831 static int do_move_page_to_node_array(struct mm_struct
*mm
,
832 struct page_to_node
*pm
,
836 struct page_to_node
*pp
;
839 down_read(&mm
->mmap_sem
);
842 * Build a list of pages to migrate
844 for (pp
= pm
; pp
->node
!= MAX_NUMNODES
; pp
++) {
845 struct vm_area_struct
*vma
;
849 vma
= find_vma(mm
, pp
->addr
);
850 if (!vma
|| !vma_migratable(vma
))
853 page
= follow_page(vma
, pp
->addr
, FOLL_GET
);
863 if (PageReserved(page
)) /* Check for zero page */
867 err
= page_to_nid(page
);
871 * Node already in the right place
876 if (page_mapcount(page
) > 1 &&
880 err
= isolate_lru_page(page
);
882 list_add_tail(&page
->lru
, &pagelist
);
885 * Either remove the duplicate refcount from
886 * isolate_lru_page() or drop the page ref if it was
895 if (!list_empty(&pagelist
))
896 err
= migrate_pages(&pagelist
, new_page_node
,
899 up_read(&mm
->mmap_sem
);
904 * Migrate an array of page address onto an array of nodes and fill
905 * the corresponding array of status.
907 static int do_pages_move(struct mm_struct
*mm
, struct task_struct
*task
,
908 unsigned long nr_pages
,
909 const void __user
* __user
*pages
,
910 const int __user
*nodes
,
911 int __user
*status
, int flags
)
913 struct page_to_node
*pm
;
914 nodemask_t task_nodes
;
915 unsigned long chunk_nr_pages
;
916 unsigned long chunk_start
;
919 task_nodes
= cpuset_mems_allowed(task
);
922 pm
= (struct page_to_node
*)__get_free_page(GFP_KERNEL
);
929 * Store a chunk of page_to_node array in a page,
930 * but keep the last one as a marker
932 chunk_nr_pages
= (PAGE_SIZE
/ sizeof(struct page_to_node
)) - 1;
934 for (chunk_start
= 0;
935 chunk_start
< nr_pages
;
936 chunk_start
+= chunk_nr_pages
) {
939 if (chunk_start
+ chunk_nr_pages
> nr_pages
)
940 chunk_nr_pages
= nr_pages
- chunk_start
;
942 /* fill the chunk pm with addrs and nodes from user-space */
943 for (j
= 0; j
< chunk_nr_pages
; j
++) {
944 const void __user
*p
;
948 if (get_user(p
, pages
+ j
+ chunk_start
))
950 pm
[j
].addr
= (unsigned long) p
;
952 if (get_user(node
, nodes
+ j
+ chunk_start
))
956 if (!node_state(node
, N_HIGH_MEMORY
))
960 if (!node_isset(node
, task_nodes
))
966 /* End marker for this chunk */
967 pm
[chunk_nr_pages
].node
= MAX_NUMNODES
;
969 /* Migrate this chunk */
970 err
= do_move_page_to_node_array(mm
, pm
,
971 flags
& MPOL_MF_MOVE_ALL
);
975 /* Return status information */
976 for (j
= 0; j
< chunk_nr_pages
; j
++)
977 if (put_user(pm
[j
].status
, status
+ j
+ chunk_start
)) {
985 free_page((unsigned long)pm
);
991 * Determine the nodes of an array of pages and store it in an array of status.
993 static void do_pages_stat_array(struct mm_struct
*mm
, unsigned long nr_pages
,
994 const void __user
**pages
, int *status
)
998 down_read(&mm
->mmap_sem
);
1000 for (i
= 0; i
< nr_pages
; i
++) {
1001 unsigned long addr
= (unsigned long)(*pages
);
1002 struct vm_area_struct
*vma
;
1006 vma
= find_vma(mm
, addr
);
1010 page
= follow_page(vma
, addr
, 0);
1012 err
= PTR_ERR(page
);
1017 /* Use PageReserved to check for zero page */
1018 if (!page
|| PageReserved(page
))
1021 err
= page_to_nid(page
);
1029 up_read(&mm
->mmap_sem
);
1033 * Determine the nodes of a user array of pages and store it in
1034 * a user array of status.
1036 static int do_pages_stat(struct mm_struct
*mm
, unsigned long nr_pages
,
1037 const void __user
* __user
*pages
,
1040 #define DO_PAGES_STAT_CHUNK_NR 16
1041 const void __user
*chunk_pages
[DO_PAGES_STAT_CHUNK_NR
];
1042 int chunk_status
[DO_PAGES_STAT_CHUNK_NR
];
1043 unsigned long i
, chunk_nr
= DO_PAGES_STAT_CHUNK_NR
;
1046 for (i
= 0; i
< nr_pages
; i
+= chunk_nr
) {
1047 if (chunk_nr
+ i
> nr_pages
)
1048 chunk_nr
= nr_pages
- i
;
1050 err
= copy_from_user(chunk_pages
, &pages
[i
],
1051 chunk_nr
* sizeof(*chunk_pages
));
1057 do_pages_stat_array(mm
, chunk_nr
, chunk_pages
, chunk_status
);
1059 err
= copy_to_user(&status
[i
], chunk_status
,
1060 chunk_nr
* sizeof(*chunk_status
));
1073 * Move a list of pages in the address space of the currently executing
1076 SYSCALL_DEFINE6(move_pages
, pid_t
, pid
, unsigned long, nr_pages
,
1077 const void __user
* __user
*, pages
,
1078 const int __user
*, nodes
,
1079 int __user
*, status
, int, flags
)
1081 const struct cred
*cred
= current_cred(), *tcred
;
1082 struct task_struct
*task
;
1083 struct mm_struct
*mm
;
1087 if (flags
& ~(MPOL_MF_MOVE
|MPOL_MF_MOVE_ALL
))
1090 if ((flags
& MPOL_MF_MOVE_ALL
) && !capable(CAP_SYS_NICE
))
1093 /* Find the mm_struct */
1094 read_lock(&tasklist_lock
);
1095 task
= pid
? find_task_by_vpid(pid
) : current
;
1097 read_unlock(&tasklist_lock
);
1100 mm
= get_task_mm(task
);
1101 read_unlock(&tasklist_lock
);
1107 * Check if this process has the right to modify the specified
1108 * process. The right exists if the process has administrative
1109 * capabilities, superuser privileges or the same
1110 * userid as the target process.
1113 tcred
= __task_cred(task
);
1114 if (cred
->euid
!= tcred
->suid
&& cred
->euid
!= tcred
->uid
&&
1115 cred
->uid
!= tcred
->suid
&& cred
->uid
!= tcred
->uid
&&
1116 !capable(CAP_SYS_NICE
)) {
1123 err
= security_task_movememory(task
);
1128 err
= do_pages_move(mm
, task
, nr_pages
, pages
, nodes
, status
,
1131 err
= do_pages_stat(mm
, nr_pages
, pages
, status
);
1140 * Call migration functions in the vma_ops that may prepare
1141 * memory in a vm for migration. migration functions may perform
1142 * the migration for vmas that do not have an underlying page struct.
1144 int migrate_vmas(struct mm_struct
*mm
, const nodemask_t
*to
,
1145 const nodemask_t
*from
, unsigned long flags
)
1147 struct vm_area_struct
*vma
;
1150 for (vma
= mm
->mmap
; vma
&& !err
; vma
= vma
->vm_next
) {
1151 if (vma
->vm_ops
&& vma
->vm_ops
->migrate
) {
1152 err
= vma
->vm_ops
->migrate(vma
, to
, from
, flags
);