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
;
177 * We hold the mmap_sem lock. So no need to call page_lock_anon_vma.
179 anon_vma
= page_anon_vma(new);
183 spin_lock(&anon_vma
->lock
);
185 list_for_each_entry(vma
, &anon_vma
->head
, anon_vma_node
)
186 remove_migration_pte(vma
, old
, new);
188 spin_unlock(&anon_vma
->lock
);
192 * Get rid of all migration entries and replace them by
193 * references to the indicated page.
195 static void remove_migration_ptes(struct page
*old
, struct page
*new)
198 remove_anon_migration_ptes(old
, new);
200 remove_file_migration_ptes(old
, new);
204 * Something used the pte of a page under migration. We need to
205 * get to the page and wait until migration is finished.
206 * When we return from this function the fault will be retried.
208 * This function is called from do_swap_page().
210 void migration_entry_wait(struct mm_struct
*mm
, pmd_t
*pmd
,
211 unsigned long address
)
218 ptep
= pte_offset_map_lock(mm
, pmd
, address
, &ptl
);
220 if (!is_swap_pte(pte
))
223 entry
= pte_to_swp_entry(pte
);
224 if (!is_migration_entry(entry
))
227 page
= migration_entry_to_page(entry
);
230 * Once radix-tree replacement of page migration started, page_count
231 * *must* be zero. And, we don't want to call wait_on_page_locked()
232 * against a page without get_page().
233 * So, we use get_page_unless_zero(), here. Even failed, page fault
236 if (!get_page_unless_zero(page
))
238 pte_unmap_unlock(ptep
, ptl
);
239 wait_on_page_locked(page
);
243 pte_unmap_unlock(ptep
, ptl
);
247 * Replace the page in the mapping.
249 * The number of remaining references must be:
250 * 1 for anonymous pages without a mapping
251 * 2 for pages with a mapping
252 * 3 for pages with a mapping and PagePrivate/PagePrivate2 set.
254 static int migrate_page_move_mapping(struct address_space
*mapping
,
255 struct page
*newpage
, struct page
*page
)
261 /* Anonymous page without mapping */
262 if (page_count(page
) != 1)
267 spin_lock_irq(&mapping
->tree_lock
);
269 pslot
= radix_tree_lookup_slot(&mapping
->page_tree
,
272 expected_count
= 2 + page_has_private(page
);
273 if (page_count(page
) != expected_count
||
274 (struct page
*)radix_tree_deref_slot(pslot
) != page
) {
275 spin_unlock_irq(&mapping
->tree_lock
);
279 if (!page_freeze_refs(page
, expected_count
)) {
280 spin_unlock_irq(&mapping
->tree_lock
);
285 * Now we know that no one else is looking at the page.
287 get_page(newpage
); /* add cache reference */
288 if (PageSwapCache(page
)) {
289 SetPageSwapCache(newpage
);
290 set_page_private(newpage
, page_private(page
));
293 radix_tree_replace_slot(pslot
, newpage
);
295 page_unfreeze_refs(page
, expected_count
);
297 * Drop cache reference from old page.
298 * We know this isn't the last reference.
303 * If moved to a different zone then also account
304 * the page for that zone. Other VM counters will be
305 * taken care of when we establish references to the
306 * new page and drop references to the old page.
308 * Note that anonymous pages are accounted for
309 * via NR_FILE_PAGES and NR_ANON_PAGES if they
310 * are mapped to swap space.
312 __dec_zone_page_state(page
, NR_FILE_PAGES
);
313 __inc_zone_page_state(newpage
, NR_FILE_PAGES
);
314 if (PageSwapBacked(page
)) {
315 __dec_zone_page_state(page
, NR_SHMEM
);
316 __inc_zone_page_state(newpage
, NR_SHMEM
);
318 spin_unlock_irq(&mapping
->tree_lock
);
324 * Copy the page to its new location
326 static void migrate_page_copy(struct page
*newpage
, struct page
*page
)
330 copy_highpage(newpage
, page
);
333 SetPageError(newpage
);
334 if (PageReferenced(page
))
335 SetPageReferenced(newpage
);
336 if (PageUptodate(page
))
337 SetPageUptodate(newpage
);
338 if (TestClearPageActive(page
)) {
339 VM_BUG_ON(PageUnevictable(page
));
340 SetPageActive(newpage
);
342 unevictable_migrate_page(newpage
, page
);
343 if (PageChecked(page
))
344 SetPageChecked(newpage
);
345 if (PageMappedToDisk(page
))
346 SetPageMappedToDisk(newpage
);
348 if (PageDirty(page
)) {
349 clear_page_dirty_for_io(page
);
351 * Want to mark the page and the radix tree as dirty, and
352 * redo the accounting that clear_page_dirty_for_io undid,
353 * but we can't use set_page_dirty because that function
354 * is actually a signal that all of the page has become dirty.
355 * Wheras only part of our page may be dirty.
357 __set_page_dirty_nobuffers(newpage
);
360 mlock_migrate_page(newpage
, page
);
362 ClearPageSwapCache(page
);
363 ClearPagePrivate(page
);
364 set_page_private(page
, 0);
365 /* page->mapping contains a flag for PageAnon() */
366 anon
= PageAnon(page
);
367 page
->mapping
= NULL
;
370 * If any waiters have accumulated on the new page then
373 if (PageWriteback(newpage
))
374 end_page_writeback(newpage
);
377 /************************************************************
378 * Migration functions
379 ***********************************************************/
381 /* Always fail migration. Used for mappings that are not movable */
382 int fail_migrate_page(struct address_space
*mapping
,
383 struct page
*newpage
, struct page
*page
)
387 EXPORT_SYMBOL(fail_migrate_page
);
390 * Common logic to directly migrate a single page suitable for
391 * pages that do not use PagePrivate/PagePrivate2.
393 * Pages are locked upon entry and exit.
395 int migrate_page(struct address_space
*mapping
,
396 struct page
*newpage
, struct page
*page
)
400 BUG_ON(PageWriteback(page
)); /* Writeback must be complete */
402 rc
= migrate_page_move_mapping(mapping
, newpage
, page
);
407 migrate_page_copy(newpage
, page
);
410 EXPORT_SYMBOL(migrate_page
);
414 * Migration function for pages with buffers. This function can only be used
415 * if the underlying filesystem guarantees that no other references to "page"
418 int buffer_migrate_page(struct address_space
*mapping
,
419 struct page
*newpage
, struct page
*page
)
421 struct buffer_head
*bh
, *head
;
424 if (!page_has_buffers(page
))
425 return migrate_page(mapping
, newpage
, page
);
427 head
= page_buffers(page
);
429 rc
= migrate_page_move_mapping(mapping
, newpage
, page
);
438 bh
= bh
->b_this_page
;
440 } while (bh
!= head
);
442 ClearPagePrivate(page
);
443 set_page_private(newpage
, page_private(page
));
444 set_page_private(page
, 0);
450 set_bh_page(bh
, newpage
, bh_offset(bh
));
451 bh
= bh
->b_this_page
;
453 } while (bh
!= head
);
455 SetPagePrivate(newpage
);
457 migrate_page_copy(newpage
, page
);
463 bh
= bh
->b_this_page
;
465 } while (bh
!= head
);
469 EXPORT_SYMBOL(buffer_migrate_page
);
473 * Writeback a page to clean the dirty state
475 static int writeout(struct address_space
*mapping
, struct page
*page
)
477 struct writeback_control wbc
= {
478 .sync_mode
= WB_SYNC_NONE
,
481 .range_end
= LLONG_MAX
,
487 if (!mapping
->a_ops
->writepage
)
488 /* No write method for the address space */
491 if (!clear_page_dirty_for_io(page
))
492 /* Someone else already triggered a write */
496 * A dirty page may imply that the underlying filesystem has
497 * the page on some queue. So the page must be clean for
498 * migration. Writeout may mean we loose the lock and the
499 * page state is no longer what we checked for earlier.
500 * At this point we know that the migration attempt cannot
503 remove_migration_ptes(page
, page
);
505 rc
= mapping
->a_ops
->writepage(page
, &wbc
);
507 if (rc
!= AOP_WRITEPAGE_ACTIVATE
)
508 /* unlocked. Relock */
511 return (rc
< 0) ? -EIO
: -EAGAIN
;
515 * Default handling if a filesystem does not provide a migration function.
517 static int fallback_migrate_page(struct address_space
*mapping
,
518 struct page
*newpage
, struct page
*page
)
521 return writeout(mapping
, page
);
524 * Buffers may be managed in a filesystem specific way.
525 * We must have no buffers or drop them.
527 if (page_has_private(page
) &&
528 !try_to_release_page(page
, GFP_KERNEL
))
531 return migrate_page(mapping
, newpage
, page
);
535 * Move a page to a newly allocated page
536 * The page is locked and all ptes have been successfully removed.
538 * The new page will have replaced the old page if this function
545 static int move_to_new_page(struct page
*newpage
, struct page
*page
)
547 struct address_space
*mapping
;
551 * Block others from accessing the page when we get around to
552 * establishing additional references. We are the only one
553 * holding a reference to the new page at this point.
555 if (!trylock_page(newpage
))
558 /* Prepare mapping for the new page.*/
559 newpage
->index
= page
->index
;
560 newpage
->mapping
= page
->mapping
;
561 if (PageSwapBacked(page
))
562 SetPageSwapBacked(newpage
);
564 mapping
= page_mapping(page
);
566 rc
= migrate_page(mapping
, newpage
, page
);
567 else if (mapping
->a_ops
->migratepage
)
569 * Most pages have a mapping and most filesystems
570 * should provide a migration function. Anonymous
571 * pages are part of swap space which also has its
572 * own migration function. This is the most common
573 * path for page migration.
575 rc
= mapping
->a_ops
->migratepage(mapping
,
578 rc
= fallback_migrate_page(mapping
, newpage
, page
);
581 remove_migration_ptes(page
, newpage
);
583 newpage
->mapping
= NULL
;
585 unlock_page(newpage
);
591 * Obtain the lock on page, remove all ptes and migrate the page
592 * to the newly allocated page in newpage.
594 static int unmap_and_move(new_page_t get_new_page
, unsigned long private,
595 struct page
*page
, int force
)
599 struct page
*newpage
= get_new_page(page
, private, &result
);
602 struct mem_cgroup
*mem
= NULL
;
607 if (page_count(page
) == 1) {
608 /* page was freed from under us. So we are done. */
612 /* prepare cgroup just returns 0 or -ENOMEM */
615 if (!trylock_page(page
)) {
621 /* charge against new page */
622 charge
= mem_cgroup_prepare_migration(page
, &mem
);
623 if (charge
== -ENOMEM
) {
629 if (PageWriteback(page
)) {
632 wait_on_page_writeback(page
);
635 * By try_to_unmap(), page->mapcount goes down to 0 here. In this case,
636 * we cannot notice that anon_vma is freed while we migrates a page.
637 * This rcu_read_lock() delays freeing anon_vma pointer until the end
638 * of migration. File cache pages are no problem because of page_lock()
639 * File Caches may use write_page() or lock_page() in migration, then,
640 * just care Anon page here.
642 if (PageAnon(page
)) {
648 * Corner case handling:
649 * 1. When a new swap-cache page is read into, it is added to the LRU
650 * and treated as swapcache but it has no rmap yet.
651 * Calling try_to_unmap() against a page->mapping==NULL page will
652 * trigger a BUG. So handle it here.
653 * 2. An orphaned page (see truncate_complete_page) might have
654 * fs-private metadata. The page can be picked up due to memory
655 * offlining. Everywhere else except page reclaim, the page is
656 * invisible to the vm, so the page can not be migrated. So try to
657 * free the metadata, so the page can be freed.
659 if (!page
->mapping
) {
660 if (!PageAnon(page
) && page_has_private(page
)) {
662 * Go direct to try_to_free_buffers() here because
663 * a) that's what try_to_release_page() would do anyway
664 * b) we may be under rcu_read_lock() here, so we can't
665 * use GFP_KERNEL which is what try_to_release_page()
666 * needs to be effective.
668 try_to_free_buffers(page
);
674 /* Establish migration ptes or remove ptes */
675 try_to_unmap(page
, TTU_MIGRATION
|TTU_IGNORE_MLOCK
|TTU_IGNORE_ACCESS
);
678 if (!page_mapped(page
))
679 rc
= move_to_new_page(newpage
, page
);
682 remove_migration_ptes(page
, page
);
688 mem_cgroup_end_migration(mem
, page
, newpage
);
694 * A page that has been migrated has all references
695 * removed and will be freed. A page that has not been
696 * migrated will have kepts its references and be
699 list_del(&page
->lru
);
700 dec_zone_page_state(page
, NR_ISOLATED_ANON
+
701 page_is_file_cache(page
));
702 putback_lru_page(page
);
708 * Move the new page to the LRU. If migration was not successful
709 * then this will free the page.
711 putback_lru_page(newpage
);
717 *result
= page_to_nid(newpage
);
725 * The function takes one list of pages to migrate and a function
726 * that determines from the page to be migrated and the private data
727 * the target of the move and allocates the page.
729 * The function returns after 10 attempts or if no pages
730 * are movable anymore because to has become empty
731 * or no retryable pages exist anymore. All pages will be
732 * returned to the LRU or freed.
734 * Return: Number of pages not migrated or error code.
736 int migrate_pages(struct list_head
*from
,
737 new_page_t get_new_page
, unsigned long private)
744 int swapwrite
= current
->flags
& PF_SWAPWRITE
;
748 current
->flags
|= PF_SWAPWRITE
;
750 for(pass
= 0; pass
< 10 && retry
; pass
++) {
753 list_for_each_entry_safe(page
, page2
, from
, lru
) {
756 rc
= unmap_and_move(get_new_page
, private,
768 /* Permanent failure */
777 current
->flags
&= ~PF_SWAPWRITE
;
779 putback_lru_pages(from
);
784 return nr_failed
+ retry
;
789 * Move a list of individual pages
791 struct page_to_node
{
798 static struct page
*new_page_node(struct page
*p
, unsigned long private,
801 struct page_to_node
*pm
= (struct page_to_node
*)private;
803 while (pm
->node
!= MAX_NUMNODES
&& pm
->page
!= p
)
806 if (pm
->node
== MAX_NUMNODES
)
809 *result
= &pm
->status
;
811 return alloc_pages_exact_node(pm
->node
,
812 GFP_HIGHUSER_MOVABLE
| GFP_THISNODE
, 0);
816 * Move a set of pages as indicated in the pm array. The addr
817 * field must be set to the virtual address of the page to be moved
818 * and the node number must contain a valid target node.
819 * The pm array ends with node = MAX_NUMNODES.
821 static int do_move_page_to_node_array(struct mm_struct
*mm
,
822 struct page_to_node
*pm
,
826 struct page_to_node
*pp
;
829 down_read(&mm
->mmap_sem
);
832 * Build a list of pages to migrate
834 for (pp
= pm
; pp
->node
!= MAX_NUMNODES
; pp
++) {
835 struct vm_area_struct
*vma
;
839 vma
= find_vma(mm
, pp
->addr
);
840 if (!vma
|| !vma_migratable(vma
))
843 page
= follow_page(vma
, pp
->addr
, FOLL_GET
);
853 if (PageReserved(page
)) /* Check for zero page */
857 err
= page_to_nid(page
);
861 * Node already in the right place
866 if (page_mapcount(page
) > 1 &&
870 err
= isolate_lru_page(page
);
872 list_add_tail(&page
->lru
, &pagelist
);
873 inc_zone_page_state(page
, NR_ISOLATED_ANON
+
874 page_is_file_cache(page
));
878 * Either remove the duplicate refcount from
879 * isolate_lru_page() or drop the page ref if it was
888 if (!list_empty(&pagelist
))
889 err
= migrate_pages(&pagelist
, new_page_node
,
892 up_read(&mm
->mmap_sem
);
897 * Migrate an array of page address onto an array of nodes and fill
898 * the corresponding array of status.
900 static int do_pages_move(struct mm_struct
*mm
, struct task_struct
*task
,
901 unsigned long nr_pages
,
902 const void __user
* __user
*pages
,
903 const int __user
*nodes
,
904 int __user
*status
, int flags
)
906 struct page_to_node
*pm
;
907 nodemask_t task_nodes
;
908 unsigned long chunk_nr_pages
;
909 unsigned long chunk_start
;
912 task_nodes
= cpuset_mems_allowed(task
);
915 pm
= (struct page_to_node
*)__get_free_page(GFP_KERNEL
);
922 * Store a chunk of page_to_node array in a page,
923 * but keep the last one as a marker
925 chunk_nr_pages
= (PAGE_SIZE
/ sizeof(struct page_to_node
)) - 1;
927 for (chunk_start
= 0;
928 chunk_start
< nr_pages
;
929 chunk_start
+= chunk_nr_pages
) {
932 if (chunk_start
+ chunk_nr_pages
> nr_pages
)
933 chunk_nr_pages
= nr_pages
- chunk_start
;
935 /* fill the chunk pm with addrs and nodes from user-space */
936 for (j
= 0; j
< chunk_nr_pages
; j
++) {
937 const void __user
*p
;
941 if (get_user(p
, pages
+ j
+ chunk_start
))
943 pm
[j
].addr
= (unsigned long) p
;
945 if (get_user(node
, nodes
+ j
+ chunk_start
))
949 if (!node_state(node
, N_HIGH_MEMORY
))
953 if (!node_isset(node
, task_nodes
))
959 /* End marker for this chunk */
960 pm
[chunk_nr_pages
].node
= MAX_NUMNODES
;
962 /* Migrate this chunk */
963 err
= do_move_page_to_node_array(mm
, pm
,
964 flags
& MPOL_MF_MOVE_ALL
);
968 /* Return status information */
969 for (j
= 0; j
< chunk_nr_pages
; j
++)
970 if (put_user(pm
[j
].status
, status
+ j
+ chunk_start
)) {
978 free_page((unsigned long)pm
);
984 * Determine the nodes of an array of pages and store it in an array of status.
986 static void do_pages_stat_array(struct mm_struct
*mm
, unsigned long nr_pages
,
987 const void __user
**pages
, int *status
)
991 down_read(&mm
->mmap_sem
);
993 for (i
= 0; i
< nr_pages
; i
++) {
994 unsigned long addr
= (unsigned long)(*pages
);
995 struct vm_area_struct
*vma
;
999 vma
= find_vma(mm
, addr
);
1003 page
= follow_page(vma
, addr
, 0);
1005 err
= PTR_ERR(page
);
1010 /* Use PageReserved to check for zero page */
1011 if (!page
|| PageReserved(page
))
1014 err
= page_to_nid(page
);
1022 up_read(&mm
->mmap_sem
);
1026 * Determine the nodes of a user array of pages and store it in
1027 * a user array of status.
1029 static int do_pages_stat(struct mm_struct
*mm
, unsigned long nr_pages
,
1030 const void __user
* __user
*pages
,
1033 #define DO_PAGES_STAT_CHUNK_NR 16
1034 const void __user
*chunk_pages
[DO_PAGES_STAT_CHUNK_NR
];
1035 int chunk_status
[DO_PAGES_STAT_CHUNK_NR
];
1036 unsigned long i
, chunk_nr
= DO_PAGES_STAT_CHUNK_NR
;
1039 for (i
= 0; i
< nr_pages
; i
+= chunk_nr
) {
1040 if (chunk_nr
> nr_pages
- i
)
1041 chunk_nr
= nr_pages
- i
;
1043 err
= copy_from_user(chunk_pages
, &pages
[i
],
1044 chunk_nr
* sizeof(*chunk_pages
));
1050 do_pages_stat_array(mm
, chunk_nr
, chunk_pages
, chunk_status
);
1052 err
= copy_to_user(&status
[i
], chunk_status
,
1053 chunk_nr
* sizeof(*chunk_status
));
1066 * Move a list of pages in the address space of the currently executing
1069 SYSCALL_DEFINE6(move_pages
, pid_t
, pid
, unsigned long, nr_pages
,
1070 const void __user
* __user
*, pages
,
1071 const int __user
*, nodes
,
1072 int __user
*, status
, int, flags
)
1074 const struct cred
*cred
= current_cred(), *tcred
;
1075 struct task_struct
*task
;
1076 struct mm_struct
*mm
;
1080 if (flags
& ~(MPOL_MF_MOVE
|MPOL_MF_MOVE_ALL
))
1083 if ((flags
& MPOL_MF_MOVE_ALL
) && !capable(CAP_SYS_NICE
))
1086 /* Find the mm_struct */
1087 read_lock(&tasklist_lock
);
1088 task
= pid
? find_task_by_vpid(pid
) : current
;
1090 read_unlock(&tasklist_lock
);
1093 mm
= get_task_mm(task
);
1094 read_unlock(&tasklist_lock
);
1100 * Check if this process has the right to modify the specified
1101 * process. The right exists if the process has administrative
1102 * capabilities, superuser privileges or the same
1103 * userid as the target process.
1106 tcred
= __task_cred(task
);
1107 if (cred
->euid
!= tcred
->suid
&& cred
->euid
!= tcred
->uid
&&
1108 cred
->uid
!= tcred
->suid
&& cred
->uid
!= tcred
->uid
&&
1109 !capable(CAP_SYS_NICE
)) {
1116 err
= security_task_movememory(task
);
1121 err
= do_pages_move(mm
, task
, nr_pages
, pages
, nodes
, status
,
1124 err
= do_pages_stat(mm
, nr_pages
, pages
, status
);
1133 * Call migration functions in the vma_ops that may prepare
1134 * memory in a vm for migration. migration functions may perform
1135 * the migration for vmas that do not have an underlying page struct.
1137 int migrate_vmas(struct mm_struct
*mm
, const nodemask_t
*to
,
1138 const nodemask_t
*from
, unsigned long flags
)
1140 struct vm_area_struct
*vma
;
1143 for (vma
= mm
->mmap
; vma
&& !err
; vma
= vma
->vm_next
) {
1144 if (vma
->vm_ops
&& vma
->vm_ops
->migrate
) {
1145 err
= vma
->vm_ops
->migrate(vma
, to
, from
, flags
);