38e7cad782f4b008a85f03e6635332f46ba0932b
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/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/gfp.h>
39 #define lru_to_page(_head) (list_entry((_head)->prev, struct page, lru))
42 * migrate_prep() needs to be called before we start compiling a list of pages
43 * to be migrated using isolate_lru_page(). If scheduling work on other CPUs is
44 * undesirable, use migrate_prep_local()
46 int migrate_prep(void)
49 * Clear the LRU lists so pages can be isolated.
50 * Note that pages may be moved off the LRU after we have
51 * drained them. Those pages will fail to migrate like other
52 * pages that may be busy.
59 /* Do the necessary work of migrate_prep but not if it involves other CPUs */
60 int migrate_prep_local(void)
68 * Add isolated pages on the list back to the LRU under page lock
69 * to avoid leaking evictable pages back onto unevictable list.
71 void putback_lru_pages(struct list_head
*l
)
76 list_for_each_entry_safe(page
, page2
, l
, lru
) {
78 dec_zone_page_state(page
, NR_ISOLATED_ANON
+
79 page_is_file_cache(page
));
80 putback_lru_page(page
);
85 * Restore a potential migration pte to a working pte entry
87 static int remove_migration_pte(struct page
*new, struct vm_area_struct
*vma
,
88 unsigned long addr
, void *old
)
90 struct mm_struct
*mm
= vma
->vm_mm
;
98 pgd
= pgd_offset(mm
, addr
);
99 if (!pgd_present(*pgd
))
102 pud
= pud_offset(pgd
, addr
);
103 if (!pud_present(*pud
))
106 pmd
= pmd_offset(pud
, addr
);
107 if (!pmd_present(*pmd
))
110 ptep
= pte_offset_map(pmd
, addr
);
112 if (!is_swap_pte(*ptep
)) {
117 ptl
= pte_lockptr(mm
, pmd
);
120 if (!is_swap_pte(pte
))
123 entry
= pte_to_swp_entry(pte
);
125 if (!is_migration_entry(entry
) ||
126 migration_entry_to_page(entry
) != old
)
130 pte
= pte_mkold(mk_pte(new, vma
->vm_page_prot
));
131 if (is_write_migration_entry(entry
))
132 pte
= pte_mkwrite(pte
);
133 flush_cache_page(vma
, addr
, pte_pfn(pte
));
134 set_pte_at(mm
, addr
, ptep
, pte
);
137 page_add_anon_rmap(new, vma
, addr
);
139 page_add_file_rmap(new);
141 /* No need to invalidate - it was non-present before */
142 update_mmu_cache(vma
, addr
, ptep
);
144 pte_unmap_unlock(ptep
, ptl
);
150 * Get rid of all migration entries and replace them by
151 * references to the indicated page.
153 static void remove_migration_ptes(struct page
*old
, struct page
*new)
155 rmap_walk(new, remove_migration_pte
, old
);
159 * Something used the pte of a page under migration. We need to
160 * get to the page and wait until migration is finished.
161 * When we return from this function the fault will be retried.
163 * This function is called from do_swap_page().
165 void migration_entry_wait(struct mm_struct
*mm
, pmd_t
*pmd
,
166 unsigned long address
)
173 ptep
= pte_offset_map_lock(mm
, pmd
, address
, &ptl
);
175 if (!is_swap_pte(pte
))
178 entry
= pte_to_swp_entry(pte
);
179 if (!is_migration_entry(entry
))
182 page
= migration_entry_to_page(entry
);
185 * Once radix-tree replacement of page migration started, page_count
186 * *must* be zero. And, we don't want to call wait_on_page_locked()
187 * against a page without get_page().
188 * So, we use get_page_unless_zero(), here. Even failed, page fault
191 if (!get_page_unless_zero(page
))
193 pte_unmap_unlock(ptep
, ptl
);
194 wait_on_page_locked(page
);
198 pte_unmap_unlock(ptep
, ptl
);
202 * Replace the page in the mapping.
204 * The number of remaining references must be:
205 * 1 for anonymous pages without a mapping
206 * 2 for pages with a mapping
207 * 3 for pages with a mapping and PagePrivate/PagePrivate2 set.
209 static int migrate_page_move_mapping(struct address_space
*mapping
,
210 struct page
*newpage
, struct page
*page
)
216 /* Anonymous page without mapping */
217 if (page_count(page
) != 1)
222 spin_lock_irq(&mapping
->tree_lock
);
224 pslot
= radix_tree_lookup_slot(&mapping
->page_tree
,
227 expected_count
= 2 + page_has_private(page
);
228 if (page_count(page
) != expected_count
||
229 (struct page
*)radix_tree_deref_slot(pslot
) != page
) {
230 spin_unlock_irq(&mapping
->tree_lock
);
234 if (!page_freeze_refs(page
, expected_count
)) {
235 spin_unlock_irq(&mapping
->tree_lock
);
240 * Now we know that no one else is looking at the page.
242 get_page(newpage
); /* add cache reference */
243 if (PageSwapCache(page
)) {
244 SetPageSwapCache(newpage
);
245 set_page_private(newpage
, page_private(page
));
248 radix_tree_replace_slot(pslot
, newpage
);
250 page_unfreeze_refs(page
, expected_count
);
252 * Drop cache reference from old page.
253 * We know this isn't the last reference.
258 * If moved to a different zone then also account
259 * the page for that zone. Other VM counters will be
260 * taken care of when we establish references to the
261 * new page and drop references to the old page.
263 * Note that anonymous pages are accounted for
264 * via NR_FILE_PAGES and NR_ANON_PAGES if they
265 * are mapped to swap space.
267 __dec_zone_page_state(page
, NR_FILE_PAGES
);
268 __inc_zone_page_state(newpage
, NR_FILE_PAGES
);
269 if (PageSwapBacked(page
)) {
270 __dec_zone_page_state(page
, NR_SHMEM
);
271 __inc_zone_page_state(newpage
, NR_SHMEM
);
273 spin_unlock_irq(&mapping
->tree_lock
);
279 * Copy the page to its new location
281 static void migrate_page_copy(struct page
*newpage
, struct page
*page
)
283 copy_highpage(newpage
, page
);
286 SetPageError(newpage
);
287 if (PageReferenced(page
))
288 SetPageReferenced(newpage
);
289 if (PageUptodate(page
))
290 SetPageUptodate(newpage
);
291 if (TestClearPageActive(page
)) {
292 VM_BUG_ON(PageUnevictable(page
));
293 SetPageActive(newpage
);
294 } else if (TestClearPageUnevictable(page
))
295 SetPageUnevictable(newpage
);
296 if (PageChecked(page
))
297 SetPageChecked(newpage
);
298 if (PageMappedToDisk(page
))
299 SetPageMappedToDisk(newpage
);
301 if (PageDirty(page
)) {
302 clear_page_dirty_for_io(page
);
304 * Want to mark the page and the radix tree as dirty, and
305 * redo the accounting that clear_page_dirty_for_io undid,
306 * but we can't use set_page_dirty because that function
307 * is actually a signal that all of the page has become dirty.
308 * Wheras only part of our page may be dirty.
310 __set_page_dirty_nobuffers(newpage
);
313 mlock_migrate_page(newpage
, page
);
314 ksm_migrate_page(newpage
, page
);
316 ClearPageSwapCache(page
);
317 ClearPagePrivate(page
);
318 set_page_private(page
, 0);
319 page
->mapping
= NULL
;
322 * If any waiters have accumulated on the new page then
325 if (PageWriteback(newpage
))
326 end_page_writeback(newpage
);
329 /************************************************************
330 * Migration functions
331 ***********************************************************/
333 /* Always fail migration. Used for mappings that are not movable */
334 int fail_migrate_page(struct address_space
*mapping
,
335 struct page
*newpage
, struct page
*page
)
339 EXPORT_SYMBOL(fail_migrate_page
);
342 * Common logic to directly migrate a single page suitable for
343 * pages that do not use PagePrivate/PagePrivate2.
345 * Pages are locked upon entry and exit.
347 int migrate_page(struct address_space
*mapping
,
348 struct page
*newpage
, struct page
*page
)
352 BUG_ON(PageWriteback(page
)); /* Writeback must be complete */
354 rc
= migrate_page_move_mapping(mapping
, newpage
, page
);
359 migrate_page_copy(newpage
, page
);
362 EXPORT_SYMBOL(migrate_page
);
366 * Migration function for pages with buffers. This function can only be used
367 * if the underlying filesystem guarantees that no other references to "page"
370 int buffer_migrate_page(struct address_space
*mapping
,
371 struct page
*newpage
, struct page
*page
)
373 struct buffer_head
*bh
, *head
;
376 if (!page_has_buffers(page
))
377 return migrate_page(mapping
, newpage
, page
);
379 head
= page_buffers(page
);
381 rc
= migrate_page_move_mapping(mapping
, newpage
, page
);
390 bh
= bh
->b_this_page
;
392 } while (bh
!= head
);
394 ClearPagePrivate(page
);
395 set_page_private(newpage
, page_private(page
));
396 set_page_private(page
, 0);
402 set_bh_page(bh
, newpage
, bh_offset(bh
));
403 bh
= bh
->b_this_page
;
405 } while (bh
!= head
);
407 SetPagePrivate(newpage
);
409 migrate_page_copy(newpage
, page
);
415 bh
= bh
->b_this_page
;
417 } while (bh
!= head
);
421 EXPORT_SYMBOL(buffer_migrate_page
);
425 * Writeback a page to clean the dirty state
427 static int writeout(struct address_space
*mapping
, struct page
*page
)
429 struct writeback_control wbc
= {
430 .sync_mode
= WB_SYNC_NONE
,
433 .range_end
= LLONG_MAX
,
439 if (!mapping
->a_ops
->writepage
)
440 /* No write method for the address space */
443 if (!clear_page_dirty_for_io(page
))
444 /* Someone else already triggered a write */
448 * A dirty page may imply that the underlying filesystem has
449 * the page on some queue. So the page must be clean for
450 * migration. Writeout may mean we loose the lock and the
451 * page state is no longer what we checked for earlier.
452 * At this point we know that the migration attempt cannot
455 remove_migration_ptes(page
, page
);
457 rc
= mapping
->a_ops
->writepage(page
, &wbc
);
459 if (rc
!= AOP_WRITEPAGE_ACTIVATE
)
460 /* unlocked. Relock */
463 return (rc
< 0) ? -EIO
: -EAGAIN
;
467 * Default handling if a filesystem does not provide a migration function.
469 static int fallback_migrate_page(struct address_space
*mapping
,
470 struct page
*newpage
, struct page
*page
)
473 return writeout(mapping
, page
);
476 * Buffers may be managed in a filesystem specific way.
477 * We must have no buffers or drop them.
479 if (page_has_private(page
) &&
480 !try_to_release_page(page
, GFP_KERNEL
))
483 return migrate_page(mapping
, newpage
, page
);
487 * Move a page to a newly allocated page
488 * The page is locked and all ptes have been successfully removed.
490 * The new page will have replaced the old page if this function
497 static int move_to_new_page(struct page
*newpage
, struct page
*page
,
500 struct address_space
*mapping
;
504 * Block others from accessing the page when we get around to
505 * establishing additional references. We are the only one
506 * holding a reference to the new page at this point.
508 if (!trylock_page(newpage
))
511 /* Prepare mapping for the new page.*/
512 newpage
->index
= page
->index
;
513 newpage
->mapping
= page
->mapping
;
514 if (PageSwapBacked(page
))
515 SetPageSwapBacked(newpage
);
517 mapping
= page_mapping(page
);
519 rc
= migrate_page(mapping
, newpage
, page
);
520 else if (mapping
->a_ops
->migratepage
)
522 * Most pages have a mapping and most filesystems
523 * should provide a migration function. Anonymous
524 * pages are part of swap space which also has its
525 * own migration function. This is the most common
526 * path for page migration.
528 rc
= mapping
->a_ops
->migratepage(mapping
,
531 rc
= fallback_migrate_page(mapping
, newpage
, page
);
534 newpage
->mapping
= NULL
;
537 remove_migration_ptes(page
, newpage
);
540 unlock_page(newpage
);
546 * Obtain the lock on page, remove all ptes and migrate the page
547 * to the newly allocated page in newpage.
549 static int unmap_and_move(new_page_t get_new_page
, unsigned long private,
550 struct page
*page
, int force
, int offlining
)
554 struct page
*newpage
= get_new_page(page
, private, &result
);
555 int remap_swapcache
= 1;
558 struct mem_cgroup
*mem
= NULL
;
559 struct anon_vma
*anon_vma
= NULL
;
564 if (page_count(page
) == 1) {
565 /* page was freed from under us. So we are done. */
569 /* prepare cgroup just returns 0 or -ENOMEM */
572 if (!trylock_page(page
)) {
579 * Only memory hotplug's offline_pages() caller has locked out KSM,
580 * and can safely migrate a KSM page. The other cases have skipped
581 * PageKsm along with PageReserved - but it is only now when we have
582 * the page lock that we can be certain it will not go KSM beneath us
583 * (KSM will not upgrade a page from PageAnon to PageKsm when it sees
584 * its pagecount raised, but only here do we take the page lock which
587 if (PageKsm(page
) && !offlining
) {
592 /* charge against new page */
593 charge
= mem_cgroup_prepare_migration(page
, newpage
, &mem
);
594 if (charge
== -ENOMEM
) {
600 if (PageWriteback(page
)) {
603 wait_on_page_writeback(page
);
606 * By try_to_unmap(), page->mapcount goes down to 0 here. In this case,
607 * we cannot notice that anon_vma is freed while we migrates a page.
608 * This rcu_read_lock() delays freeing anon_vma pointer until the end
609 * of migration. File cache pages are no problem because of page_lock()
610 * File Caches may use write_page() or lock_page() in migration, then,
611 * just care Anon page here.
613 if (PageAnon(page
)) {
617 /* Determine how to safely use anon_vma */
618 if (!page_mapped(page
)) {
619 if (!PageSwapCache(page
))
623 * We cannot be sure that the anon_vma of an unmapped
624 * swapcache page is safe to use because we don't
625 * know in advance if the VMA that this page belonged
626 * to still exists. If the VMA and others sharing the
627 * data have been freed, then the anon_vma could
628 * already be invalid.
630 * To avoid this possibility, swapcache pages get
631 * migrated but are not remapped when migration
637 * Take a reference count on the anon_vma if the
638 * page is mapped so that it is guaranteed to
639 * exist when the page is remapped later
641 anon_vma
= page_anon_vma(page
);
642 get_anon_vma(anon_vma
);
647 * Corner case handling:
648 * 1. When a new swap-cache page is read into, it is added to the LRU
649 * and treated as swapcache but it has no rmap yet.
650 * Calling try_to_unmap() against a page->mapping==NULL page will
651 * trigger a BUG. So handle it here.
652 * 2. An orphaned page (see truncate_complete_page) might have
653 * fs-private metadata. The page can be picked up due to memory
654 * offlining. Everywhere else except page reclaim, the page is
655 * invisible to the vm, so the page can not be migrated. So try to
656 * free the metadata, so the page can be freed.
658 if (!page
->mapping
) {
659 if (!PageAnon(page
) && page_has_private(page
)) {
661 * Go direct to try_to_free_buffers() here because
662 * a) that's what try_to_release_page() would do anyway
663 * b) we may be under rcu_read_lock() here, so we can't
664 * use GFP_KERNEL which is what try_to_release_page()
665 * needs to be effective.
667 try_to_free_buffers(page
);
673 /* Establish migration ptes or remove ptes */
674 try_to_unmap(page
, TTU_MIGRATION
|TTU_IGNORE_MLOCK
|TTU_IGNORE_ACCESS
);
677 if (!page_mapped(page
))
678 rc
= move_to_new_page(newpage
, page
, remap_swapcache
);
680 if (rc
&& remap_swapcache
)
681 remove_migration_ptes(page
, page
);
684 /* Drop an anon_vma reference if we took one */
686 drop_anon_vma(anon_vma
);
692 mem_cgroup_end_migration(mem
, page
, newpage
);
698 * A page that has been migrated has all references
699 * removed and will be freed. A page that has not been
700 * migrated will have kepts its references and be
703 list_del(&page
->lru
);
704 dec_zone_page_state(page
, NR_ISOLATED_ANON
+
705 page_is_file_cache(page
));
706 putback_lru_page(page
);
712 * Move the new page to the LRU. If migration was not successful
713 * then this will free the page.
715 putback_lru_page(newpage
);
721 *result
= page_to_nid(newpage
);
729 * The function takes one list of pages to migrate and a function
730 * that determines from the page to be migrated and the private data
731 * the target of the move and allocates the page.
733 * The function returns after 10 attempts or if no pages
734 * are movable anymore because to has become empty
735 * or no retryable pages exist anymore. All pages will be
736 * returned to the LRU or freed.
738 * Return: Number of pages not migrated or error code.
740 int migrate_pages(struct list_head
*from
,
741 new_page_t get_new_page
, unsigned long private, int offlining
)
748 int swapwrite
= current
->flags
& PF_SWAPWRITE
;
752 current
->flags
|= PF_SWAPWRITE
;
754 for(pass
= 0; pass
< 10 && retry
; pass
++) {
757 list_for_each_entry_safe(page
, page2
, from
, lru
) {
760 rc
= unmap_and_move(get_new_page
, private,
761 page
, pass
> 2, offlining
);
772 /* Permanent failure */
781 current
->flags
&= ~PF_SWAPWRITE
;
783 putback_lru_pages(from
);
788 return nr_failed
+ retry
;
793 * Move a list of individual pages
795 struct page_to_node
{
802 static struct page
*new_page_node(struct page
*p
, unsigned long private,
805 struct page_to_node
*pm
= (struct page_to_node
*)private;
807 while (pm
->node
!= MAX_NUMNODES
&& pm
->page
!= p
)
810 if (pm
->node
== MAX_NUMNODES
)
813 *result
= &pm
->status
;
815 return alloc_pages_exact_node(pm
->node
,
816 GFP_HIGHUSER_MOVABLE
| GFP_THISNODE
, 0);
820 * Move a set of pages as indicated in the pm array. The addr
821 * field must be set to the virtual address of the page to be moved
822 * and the node number must contain a valid target node.
823 * The pm array ends with node = MAX_NUMNODES.
825 static int do_move_page_to_node_array(struct mm_struct
*mm
,
826 struct page_to_node
*pm
,
830 struct page_to_node
*pp
;
833 down_read(&mm
->mmap_sem
);
836 * Build a list of pages to migrate
838 for (pp
= pm
; pp
->node
!= MAX_NUMNODES
; pp
++) {
839 struct vm_area_struct
*vma
;
843 vma
= find_vma(mm
, pp
->addr
);
844 if (!vma
|| !vma_migratable(vma
))
847 page
= follow_page(vma
, pp
->addr
, FOLL_GET
);
857 /* Use PageReserved to check for zero page */
858 if (PageReserved(page
) || PageKsm(page
))
862 err
= page_to_nid(page
);
866 * Node already in the right place
871 if (page_mapcount(page
) > 1 &&
875 err
= isolate_lru_page(page
);
877 list_add_tail(&page
->lru
, &pagelist
);
878 inc_zone_page_state(page
, NR_ISOLATED_ANON
+
879 page_is_file_cache(page
));
883 * Either remove the duplicate refcount from
884 * isolate_lru_page() or drop the page ref if it was
893 if (!list_empty(&pagelist
))
894 err
= migrate_pages(&pagelist
, new_page_node
,
895 (unsigned long)pm
, 0);
897 up_read(&mm
->mmap_sem
);
902 * Migrate an array of page address onto an array of nodes and fill
903 * the corresponding array of status.
905 static int do_pages_move(struct mm_struct
*mm
, struct task_struct
*task
,
906 unsigned long nr_pages
,
907 const void __user
* __user
*pages
,
908 const int __user
*nodes
,
909 int __user
*status
, int flags
)
911 struct page_to_node
*pm
;
912 nodemask_t task_nodes
;
913 unsigned long chunk_nr_pages
;
914 unsigned long chunk_start
;
917 task_nodes
= cpuset_mems_allowed(task
);
920 pm
= (struct page_to_node
*)__get_free_page(GFP_KERNEL
);
927 * Store a chunk of page_to_node array in a page,
928 * but keep the last one as a marker
930 chunk_nr_pages
= (PAGE_SIZE
/ sizeof(struct page_to_node
)) - 1;
932 for (chunk_start
= 0;
933 chunk_start
< nr_pages
;
934 chunk_start
+= chunk_nr_pages
) {
937 if (chunk_start
+ chunk_nr_pages
> nr_pages
)
938 chunk_nr_pages
= nr_pages
- chunk_start
;
940 /* fill the chunk pm with addrs and nodes from user-space */
941 for (j
= 0; j
< chunk_nr_pages
; j
++) {
942 const void __user
*p
;
946 if (get_user(p
, pages
+ j
+ chunk_start
))
948 pm
[j
].addr
= (unsigned long) p
;
950 if (get_user(node
, nodes
+ j
+ chunk_start
))
954 if (node
< 0 || node
>= MAX_NUMNODES
)
957 if (!node_state(node
, N_HIGH_MEMORY
))
961 if (!node_isset(node
, task_nodes
))
967 /* End marker for this chunk */
968 pm
[chunk_nr_pages
].node
= MAX_NUMNODES
;
970 /* Migrate this chunk */
971 err
= do_move_page_to_node_array(mm
, pm
,
972 flags
& MPOL_MF_MOVE_ALL
);
976 /* Return status information */
977 for (j
= 0; j
< chunk_nr_pages
; j
++)
978 if (put_user(pm
[j
].status
, status
+ j
+ chunk_start
)) {
986 free_page((unsigned long)pm
);
992 * Determine the nodes of an array of pages and store it in an array of status.
994 static void do_pages_stat_array(struct mm_struct
*mm
, unsigned long nr_pages
,
995 const void __user
**pages
, int *status
)
999 down_read(&mm
->mmap_sem
);
1001 for (i
= 0; i
< nr_pages
; i
++) {
1002 unsigned long addr
= (unsigned long)(*pages
);
1003 struct vm_area_struct
*vma
;
1007 vma
= find_vma(mm
, addr
);
1011 page
= follow_page(vma
, addr
, 0);
1013 err
= PTR_ERR(page
);
1018 /* Use PageReserved to check for zero page */
1019 if (!page
|| PageReserved(page
) || PageKsm(page
))
1022 err
= page_to_nid(page
);
1030 up_read(&mm
->mmap_sem
);
1034 * Determine the nodes of a user array of pages and store it in
1035 * a user array of status.
1037 static int do_pages_stat(struct mm_struct
*mm
, unsigned long nr_pages
,
1038 const void __user
* __user
*pages
,
1041 #define DO_PAGES_STAT_CHUNK_NR 16
1042 const void __user
*chunk_pages
[DO_PAGES_STAT_CHUNK_NR
];
1043 int chunk_status
[DO_PAGES_STAT_CHUNK_NR
];
1046 unsigned long chunk_nr
;
1048 chunk_nr
= nr_pages
;
1049 if (chunk_nr
> DO_PAGES_STAT_CHUNK_NR
)
1050 chunk_nr
= DO_PAGES_STAT_CHUNK_NR
;
1052 if (copy_from_user(chunk_pages
, pages
, chunk_nr
* sizeof(*chunk_pages
)))
1055 do_pages_stat_array(mm
, chunk_nr
, chunk_pages
, chunk_status
);
1057 if (copy_to_user(status
, chunk_status
, chunk_nr
* sizeof(*status
)))
1062 nr_pages
-= chunk_nr
;
1064 return nr_pages
? -EFAULT
: 0;
1068 * Move a list of pages in the address space of the currently executing
1071 SYSCALL_DEFINE6(move_pages
, pid_t
, pid
, unsigned long, nr_pages
,
1072 const void __user
* __user
*, pages
,
1073 const int __user
*, nodes
,
1074 int __user
*, status
, int, flags
)
1076 const struct cred
*cred
= current_cred(), *tcred
;
1077 struct task_struct
*task
;
1078 struct mm_struct
*mm
;
1082 if (flags
& ~(MPOL_MF_MOVE
|MPOL_MF_MOVE_ALL
))
1085 if ((flags
& MPOL_MF_MOVE_ALL
) && !capable(CAP_SYS_NICE
))
1088 /* Find the mm_struct */
1089 read_lock(&tasklist_lock
);
1090 task
= pid
? find_task_by_vpid(pid
) : current
;
1092 read_unlock(&tasklist_lock
);
1095 mm
= get_task_mm(task
);
1096 read_unlock(&tasklist_lock
);
1102 * Check if this process has the right to modify the specified
1103 * process. The right exists if the process has administrative
1104 * capabilities, superuser privileges or the same
1105 * userid as the target process.
1108 tcred
= __task_cred(task
);
1109 if (cred
->euid
!= tcred
->suid
&& cred
->euid
!= tcred
->uid
&&
1110 cred
->uid
!= tcred
->suid
&& cred
->uid
!= tcred
->uid
&&
1111 !capable(CAP_SYS_NICE
)) {
1118 err
= security_task_movememory(task
);
1123 err
= do_pages_move(mm
, task
, nr_pages
, pages
, nodes
, status
,
1126 err
= do_pages_stat(mm
, nr_pages
, pages
, status
);
1135 * Call migration functions in the vma_ops that may prepare
1136 * memory in a vm for migration. migration functions may perform
1137 * the migration for vmas that do not have an underlying page struct.
1139 int migrate_vmas(struct mm_struct
*mm
, const nodemask_t
*to
,
1140 const nodemask_t
*from
, unsigned long flags
)
1142 struct vm_area_struct
*vma
;
1145 for (vma
= mm
->mmap
; vma
&& !err
; vma
= vma
->vm_next
) {
1146 if (vma
->vm_ops
&& vma
->vm_ops
->migrate
) {
1147 err
= vma
->vm_ops
->migrate(vma
, to
, from
, flags
);
This page took 0.054544 seconds and 5 git commands to generate.