ia64/linux-2.6.18-xen.hg

view mm/migrate.c @ 749:2892ca2b9c17

linux/x86: cleanup IO-APIC code

- get 32-bit code in sync with 64-bit wrt ExtINT pin detection being
unnecessary
- eliminate build warnings resulting from c/s 725

Signed-off-by: Jan Beulich <jbeulich@novell.com>
author Keir Fraser <keir.fraser@citrix.com>
date Fri Nov 28 13:31:21 2008 +0000 (2008-11-28)
parents 3e8752eb6d9c
children
line source
1 /*
2 * Memory Migration functionality - linux/mm/migration.c
3 *
4 * Copyright (C) 2006 Silicon Graphics, Inc., Christoph Lameter
5 *
6 * Page migration was first developed in the context of the memory hotplug
7 * project. The main authors of the migration code are:
8 *
9 * IWAMOTO Toshihiro <iwamoto@valinux.co.jp>
10 * Hirokazu Takahashi <taka@valinux.co.jp>
11 * Dave Hansen <haveblue@us.ibm.com>
12 * Christoph Lameter <clameter@sgi.com>
13 */
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/pagevec.h>
23 #include <linux/rmap.h>
24 #include <linux/topology.h>
25 #include <linux/cpu.h>
26 #include <linux/cpuset.h>
27 #include <linux/writeback.h>
28 #include <linux/mempolicy.h>
29 #include <linux/vmalloc.h>
30 #include <linux/security.h>
32 #include "internal.h"
34 #define lru_to_page(_head) (list_entry((_head)->prev, struct page, lru))
36 /*
37 * Isolate one page from the LRU lists. If successful put it onto
38 * the indicated list with elevated page count.
39 *
40 * Result:
41 * -EBUSY: page not on LRU list
42 * 0: page removed from LRU list and added to the specified list.
43 */
44 int isolate_lru_page(struct page *page, struct list_head *pagelist)
45 {
46 int ret = -EBUSY;
48 if (PageLRU(page)) {
49 struct zone *zone = page_zone(page);
51 spin_lock_irq(&zone->lru_lock);
52 if (PageLRU(page)) {
53 ret = 0;
54 get_page(page);
55 ClearPageLRU(page);
56 if (PageActive(page))
57 del_page_from_active_list(zone, page);
58 else
59 del_page_from_inactive_list(zone, page);
60 list_add_tail(&page->lru, pagelist);
61 }
62 spin_unlock_irq(&zone->lru_lock);
63 }
64 return ret;
65 }
67 /*
68 * migrate_prep() needs to be called before we start compiling a list of pages
69 * to be migrated using isolate_lru_page().
70 */
71 int migrate_prep(void)
72 {
73 /*
74 * Clear the LRU lists so pages can be isolated.
75 * Note that pages may be moved off the LRU after we have
76 * drained them. Those pages will fail to migrate like other
77 * pages that may be busy.
78 */
79 lru_add_drain_all();
81 return 0;
82 }
84 static inline void move_to_lru(struct page *page)
85 {
86 if (PageActive(page)) {
87 /*
88 * lru_cache_add_active checks that
89 * the PG_active bit is off.
90 */
91 ClearPageActive(page);
92 lru_cache_add_active(page);
93 } else {
94 lru_cache_add(page);
95 }
96 put_page(page);
97 }
99 /*
100 * Add isolated pages on the list back to the LRU.
101 *
102 * returns the number of pages put back.
103 */
104 int putback_lru_pages(struct list_head *l)
105 {
106 struct page *page;
107 struct page *page2;
108 int count = 0;
110 list_for_each_entry_safe(page, page2, l, lru) {
111 list_del(&page->lru);
112 move_to_lru(page);
113 count++;
114 }
115 return count;
116 }
118 static inline int is_swap_pte(pte_t pte)
119 {
120 return !pte_none(pte) && !pte_present(pte) && !pte_file(pte);
121 }
123 /*
124 * Restore a potential migration pte to a working pte entry
125 */
126 static void remove_migration_pte(struct vm_area_struct *vma,
127 struct page *old, struct page *new)
128 {
129 struct mm_struct *mm = vma->vm_mm;
130 swp_entry_t entry;
131 pgd_t *pgd;
132 pud_t *pud;
133 pmd_t *pmd;
134 pte_t *ptep, pte;
135 spinlock_t *ptl;
136 unsigned long addr = page_address_in_vma(new, vma);
138 if (addr == -EFAULT)
139 return;
141 pgd = pgd_offset(mm, addr);
142 if (!pgd_present(*pgd))
143 return;
145 pud = pud_offset(pgd, addr);
146 if (!pud_present(*pud))
147 return;
149 pmd = pmd_offset(pud, addr);
150 if (!pmd_present(*pmd))
151 return;
153 ptep = pte_offset_map(pmd, addr);
155 if (!is_swap_pte(*ptep)) {
156 pte_unmap(ptep);
157 return;
158 }
160 ptl = pte_lockptr(mm, pmd);
161 spin_lock(ptl);
162 pte = *ptep;
163 if (!is_swap_pte(pte))
164 goto out;
166 entry = pte_to_swp_entry(pte);
168 if (!is_migration_entry(entry) || migration_entry_to_page(entry) != old)
169 goto out;
171 get_page(new);
172 pte = pte_mkold(mk_pte(new, vma->vm_page_prot));
173 if (is_write_migration_entry(entry))
174 pte = pte_mkwrite(pte);
175 set_pte_at(mm, addr, ptep, pte);
177 if (PageAnon(new))
178 page_add_anon_rmap(new, vma, addr);
179 else
180 page_add_file_rmap(new);
182 /* No need to invalidate - it was non-present before */
183 update_mmu_cache(vma, addr, pte);
184 lazy_mmu_prot_update(pte);
186 out:
187 pte_unmap_unlock(ptep, ptl);
188 }
190 /*
191 * Note that remove_file_migration_ptes will only work on regular mappings,
192 * Nonlinear mappings do not use migration entries.
193 */
194 static void remove_file_migration_ptes(struct page *old, struct page *new)
195 {
196 struct vm_area_struct *vma;
197 struct address_space *mapping = page_mapping(new);
198 struct prio_tree_iter iter;
199 pgoff_t pgoff = new->index << (PAGE_CACHE_SHIFT - PAGE_SHIFT);
201 if (!mapping)
202 return;
204 spin_lock(&mapping->i_mmap_lock);
206 vma_prio_tree_foreach(vma, &iter, &mapping->i_mmap, pgoff, pgoff)
207 remove_migration_pte(vma, old, new);
209 spin_unlock(&mapping->i_mmap_lock);
210 }
212 /*
213 * Must hold mmap_sem lock on at least one of the vmas containing
214 * the page so that the anon_vma cannot vanish.
215 */
216 static void remove_anon_migration_ptes(struct page *old, struct page *new)
217 {
218 struct anon_vma *anon_vma;
219 struct vm_area_struct *vma;
220 unsigned long mapping;
222 mapping = (unsigned long)new->mapping;
224 if (!mapping || (mapping & PAGE_MAPPING_ANON) == 0)
225 return;
227 /*
228 * We hold the mmap_sem lock. So no need to call page_lock_anon_vma.
229 */
230 anon_vma = (struct anon_vma *) (mapping - PAGE_MAPPING_ANON);
231 spin_lock(&anon_vma->lock);
233 list_for_each_entry(vma, &anon_vma->head, anon_vma_node)
234 remove_migration_pte(vma, old, new);
236 spin_unlock(&anon_vma->lock);
237 }
239 /*
240 * Get rid of all migration entries and replace them by
241 * references to the indicated page.
242 */
243 static void remove_migration_ptes(struct page *old, struct page *new)
244 {
245 if (PageAnon(new))
246 remove_anon_migration_ptes(old, new);
247 else
248 remove_file_migration_ptes(old, new);
249 }
251 /*
252 * Something used the pte of a page under migration. We need to
253 * get to the page and wait until migration is finished.
254 * When we return from this function the fault will be retried.
255 *
256 * This function is called from do_swap_page().
257 */
258 void migration_entry_wait(struct mm_struct *mm, pmd_t *pmd,
259 unsigned long address)
260 {
261 pte_t *ptep, pte;
262 spinlock_t *ptl;
263 swp_entry_t entry;
264 struct page *page;
266 ptep = pte_offset_map_lock(mm, pmd, address, &ptl);
267 pte = *ptep;
268 if (!is_swap_pte(pte))
269 goto out;
271 entry = pte_to_swp_entry(pte);
272 if (!is_migration_entry(entry))
273 goto out;
275 page = migration_entry_to_page(entry);
277 get_page(page);
278 pte_unmap_unlock(ptep, ptl);
279 wait_on_page_locked(page);
280 put_page(page);
281 return;
282 out:
283 pte_unmap_unlock(ptep, ptl);
284 }
286 /*
287 * Replace the page in the mapping.
288 *
289 * The number of remaining references must be:
290 * 1 for anonymous pages without a mapping
291 * 2 for pages with a mapping
292 * 3 for pages with a mapping and PagePrivate set.
293 */
294 static int migrate_page_move_mapping(struct address_space *mapping,
295 struct page *newpage, struct page *page)
296 {
297 struct page **radix_pointer;
299 if (!mapping) {
300 /* Anonymous page */
301 if (page_count(page) != 1)
302 return -EAGAIN;
303 return 0;
304 }
306 write_lock_irq(&mapping->tree_lock);
308 radix_pointer = (struct page **)radix_tree_lookup_slot(
309 &mapping->page_tree,
310 page_index(page));
312 if (page_count(page) != 2 + !!PagePrivate(page) ||
313 *radix_pointer != page) {
314 write_unlock_irq(&mapping->tree_lock);
315 return -EAGAIN;
316 }
318 /*
319 * Now we know that no one else is looking at the page.
320 */
321 get_page(newpage);
322 #ifdef CONFIG_SWAP
323 if (PageSwapCache(page)) {
324 SetPageSwapCache(newpage);
325 set_page_private(newpage, page_private(page));
326 }
327 #endif
329 *radix_pointer = newpage;
330 __put_page(page);
331 write_unlock_irq(&mapping->tree_lock);
333 return 0;
334 }
336 /*
337 * Copy the page to its new location
338 */
339 static void migrate_page_copy(struct page *newpage, struct page *page)
340 {
341 copy_highpage(newpage, page);
343 if (PageError(page))
344 SetPageError(newpage);
345 if (PageReferenced(page))
346 SetPageReferenced(newpage);
347 if (PageUptodate(page))
348 SetPageUptodate(newpage);
349 if (PageActive(page))
350 SetPageActive(newpage);
351 if (PageChecked(page))
352 SetPageChecked(newpage);
353 if (PageMappedToDisk(page))
354 SetPageMappedToDisk(newpage);
356 if (PageDirty(page)) {
357 clear_page_dirty_for_io(page);
358 set_page_dirty(newpage);
359 }
361 #ifdef CONFIG_SWAP
362 ClearPageSwapCache(page);
363 #endif
364 ClearPageActive(page);
365 ClearPagePrivate(page);
366 set_page_private(page, 0);
367 page->mapping = NULL;
369 /*
370 * If any waiters have accumulated on the new page then
371 * wake them up.
372 */
373 if (PageWriteback(newpage))
374 end_page_writeback(newpage);
375 }
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)
384 {
385 return -EIO;
386 }
387 EXPORT_SYMBOL(fail_migrate_page);
389 /*
390 * Common logic to directly migrate a single page suitable for
391 * pages that do not use PagePrivate.
392 *
393 * Pages are locked upon entry and exit.
394 */
395 int migrate_page(struct address_space *mapping,
396 struct page *newpage, struct page *page)
397 {
398 int rc;
400 BUG_ON(PageWriteback(page)); /* Writeback must be complete */
402 rc = migrate_page_move_mapping(mapping, newpage, page);
404 if (rc)
405 return rc;
407 migrate_page_copy(newpage, page);
408 return 0;
409 }
410 EXPORT_SYMBOL(migrate_page);
412 /*
413 * Migration function for pages with buffers. This function can only be used
414 * if the underlying filesystem guarantees that no other references to "page"
415 * exist.
416 */
417 int buffer_migrate_page(struct address_space *mapping,
418 struct page *newpage, struct page *page)
419 {
420 struct buffer_head *bh, *head;
421 int rc;
423 if (!page_has_buffers(page))
424 return migrate_page(mapping, newpage, page);
426 head = page_buffers(page);
428 rc = migrate_page_move_mapping(mapping, newpage, page);
430 if (rc)
431 return rc;
433 bh = head;
434 do {
435 get_bh(bh);
436 lock_buffer(bh);
437 bh = bh->b_this_page;
439 } while (bh != head);
441 ClearPagePrivate(page);
442 set_page_private(newpage, page_private(page));
443 set_page_private(page, 0);
444 put_page(page);
445 get_page(newpage);
447 bh = head;
448 do {
449 set_bh_page(bh, newpage, bh_offset(bh));
450 bh = bh->b_this_page;
452 } while (bh != head);
454 SetPagePrivate(newpage);
456 migrate_page_copy(newpage, page);
458 bh = head;
459 do {
460 unlock_buffer(bh);
461 put_bh(bh);
462 bh = bh->b_this_page;
464 } while (bh != head);
466 return 0;
467 }
468 EXPORT_SYMBOL(buffer_migrate_page);
470 /*
471 * Writeback a page to clean the dirty state
472 */
473 static int writeout(struct address_space *mapping, struct page *page)
474 {
475 struct writeback_control wbc = {
476 .sync_mode = WB_SYNC_NONE,
477 .nr_to_write = 1,
478 .range_start = 0,
479 .range_end = LLONG_MAX,
480 .nonblocking = 1,
481 .for_reclaim = 1
482 };
483 int rc;
485 if (!mapping->a_ops->writepage)
486 /* No write method for the address space */
487 return -EINVAL;
489 if (!clear_page_dirty_for_io(page))
490 /* Someone else already triggered a write */
491 return -EAGAIN;
493 /*
494 * A dirty page may imply that the underlying filesystem has
495 * the page on some queue. So the page must be clean for
496 * migration. Writeout may mean we loose the lock and the
497 * page state is no longer what we checked for earlier.
498 * At this point we know that the migration attempt cannot
499 * be successful.
500 */
501 remove_migration_ptes(page, page);
503 rc = mapping->a_ops->writepage(page, &wbc);
504 if (rc < 0)
505 /* I/O Error writing */
506 return -EIO;
508 if (rc != AOP_WRITEPAGE_ACTIVATE)
509 /* unlocked. Relock */
510 lock_page(page);
512 return -EAGAIN;
513 }
515 /*
516 * Default handling if a filesystem does not provide a migration function.
517 */
518 static int fallback_migrate_page(struct address_space *mapping,
519 struct page *newpage, struct page *page)
520 {
521 if (PageDirty(page))
522 return writeout(mapping, page);
524 /*
525 * Buffers may be managed in a filesystem specific way.
526 * We must have no buffers or drop them.
527 */
528 if (page_has_buffers(page) &&
529 !try_to_release_page(page, GFP_KERNEL))
530 return -EAGAIN;
532 return migrate_page(mapping, newpage, page);
533 }
535 /*
536 * Move a page to a newly allocated page
537 * The page is locked and all ptes have been successfully removed.
538 *
539 * The new page will have replaced the old page if this function
540 * is successful.
541 */
542 static int move_to_new_page(struct page *newpage, struct page *page)
543 {
544 struct address_space *mapping;
545 int rc;
547 /*
548 * Block others from accessing the page when we get around to
549 * establishing additional references. We are the only one
550 * holding a reference to the new page at this point.
551 */
552 if (TestSetPageLocked(newpage))
553 BUG();
555 /* Prepare mapping for the new page.*/
556 newpage->index = page->index;
557 newpage->mapping = page->mapping;
559 mapping = page_mapping(page);
560 if (!mapping)
561 rc = migrate_page(mapping, newpage, page);
562 else if (mapping->a_ops->migratepage)
563 /*
564 * Most pages have a mapping and most filesystems
565 * should provide a migration function. Anonymous
566 * pages are part of swap space which also has its
567 * own migration function. This is the most common
568 * path for page migration.
569 */
570 rc = mapping->a_ops->migratepage(mapping,
571 newpage, page);
572 else
573 rc = fallback_migrate_page(mapping, newpage, page);
575 if (!rc)
576 remove_migration_ptes(page, newpage);
577 else
578 newpage->mapping = NULL;
580 unlock_page(newpage);
582 return rc;
583 }
585 /*
586 * Obtain the lock on page, remove all ptes and migrate the page
587 * to the newly allocated page in newpage.
588 */
589 static int unmap_and_move(new_page_t get_new_page, unsigned long private,
590 struct page *page, int force)
591 {
592 int rc = 0;
593 int *result = NULL;
594 struct page *newpage = get_new_page(page, private, &result);
596 if (!newpage)
597 return -ENOMEM;
599 if (page_count(page) == 1)
600 /* page was freed from under us. So we are done. */
601 goto move_newpage;
603 rc = -EAGAIN;
604 if (TestSetPageLocked(page)) {
605 if (!force)
606 goto move_newpage;
607 lock_page(page);
608 }
610 if (PageWriteback(page)) {
611 if (!force)
612 goto unlock;
613 wait_on_page_writeback(page);
614 }
616 /*
617 * Establish migration ptes or remove ptes
618 */
619 try_to_unmap(page, 1);
620 if (!page_mapped(page))
621 rc = move_to_new_page(newpage, page);
623 if (rc)
624 remove_migration_ptes(page, page);
626 unlock:
627 unlock_page(page);
629 if (rc != -EAGAIN) {
630 /*
631 * A page that has been migrated has all references
632 * removed and will be freed. A page that has not been
633 * migrated will have kepts its references and be
634 * restored.
635 */
636 list_del(&page->lru);
637 move_to_lru(page);
638 }
640 move_newpage:
641 /*
642 * Move the new page to the LRU. If migration was not successful
643 * then this will free the page.
644 */
645 move_to_lru(newpage);
646 if (result) {
647 if (rc)
648 *result = rc;
649 else
650 *result = page_to_nid(newpage);
651 }
652 return rc;
653 }
655 /*
656 * migrate_pages
657 *
658 * The function takes one list of pages to migrate and a function
659 * that determines from the page to be migrated and the private data
660 * the target of the move and allocates the page.
661 *
662 * The function returns after 10 attempts or if no pages
663 * are movable anymore because to has become empty
664 * or no retryable pages exist anymore. All pages will be
665 * retruned to the LRU or freed.
666 *
667 * Return: Number of pages not migrated or error code.
668 */
669 int migrate_pages(struct list_head *from,
670 new_page_t get_new_page, unsigned long private)
671 {
672 int retry = 1;
673 int nr_failed = 0;
674 int pass = 0;
675 struct page *page;
676 struct page *page2;
677 int swapwrite = current->flags & PF_SWAPWRITE;
678 int rc;
680 if (!swapwrite)
681 current->flags |= PF_SWAPWRITE;
683 for(pass = 0; pass < 10 && retry; pass++) {
684 retry = 0;
686 list_for_each_entry_safe(page, page2, from, lru) {
687 cond_resched();
689 rc = unmap_and_move(get_new_page, private,
690 page, pass > 2);
692 switch(rc) {
693 case -ENOMEM:
694 goto out;
695 case -EAGAIN:
696 retry++;
697 break;
698 case 0:
699 break;
700 default:
701 /* Permanent failure */
702 nr_failed++;
703 break;
704 }
705 }
706 }
707 rc = 0;
708 out:
709 if (!swapwrite)
710 current->flags &= ~PF_SWAPWRITE;
712 putback_lru_pages(from);
714 if (rc)
715 return rc;
717 return nr_failed + retry;
718 }
720 #ifdef CONFIG_NUMA
721 /*
722 * Move a list of individual pages
723 */
724 struct page_to_node {
725 unsigned long addr;
726 struct page *page;
727 int node;
728 int status;
729 };
731 static struct page *new_page_node(struct page *p, unsigned long private,
732 int **result)
733 {
734 struct page_to_node *pm = (struct page_to_node *)private;
736 while (pm->node != MAX_NUMNODES && pm->page != p)
737 pm++;
739 if (pm->node == MAX_NUMNODES)
740 return NULL;
742 *result = &pm->status;
744 return alloc_pages_node(pm->node, GFP_HIGHUSER, 0);
745 }
747 /*
748 * Move a set of pages as indicated in the pm array. The addr
749 * field must be set to the virtual address of the page to be moved
750 * and the node number must contain a valid target node.
751 */
752 static int do_move_pages(struct mm_struct *mm, struct page_to_node *pm,
753 int migrate_all)
754 {
755 int err;
756 struct page_to_node *pp;
757 LIST_HEAD(pagelist);
759 down_read(&mm->mmap_sem);
761 /*
762 * Build a list of pages to migrate
763 */
764 migrate_prep();
765 for (pp = pm; pp->node != MAX_NUMNODES; pp++) {
766 struct vm_area_struct *vma;
767 struct page *page;
769 /*
770 * A valid page pointer that will not match any of the
771 * pages that will be moved.
772 */
773 pp->page = ZERO_PAGE(0);
775 err = -EFAULT;
776 vma = find_vma(mm, pp->addr);
777 if (!vma)
778 goto set_status;
780 page = follow_page(vma, pp->addr, FOLL_GET);
781 err = -ENOENT;
782 if (!page)
783 goto set_status;
785 if (PageReserved(page)) /* Check for zero page */
786 goto put_and_set;
788 pp->page = page;
789 err = page_to_nid(page);
791 if (err == pp->node)
792 /*
793 * Node already in the right place
794 */
795 goto put_and_set;
797 err = -EACCES;
798 if (page_mapcount(page) > 1 &&
799 !migrate_all)
800 goto put_and_set;
802 err = isolate_lru_page(page, &pagelist);
803 put_and_set:
804 /*
805 * Either remove the duplicate refcount from
806 * isolate_lru_page() or drop the page ref if it was
807 * not isolated.
808 */
809 put_page(page);
810 set_status:
811 pp->status = err;
812 }
814 if (!list_empty(&pagelist))
815 err = migrate_pages(&pagelist, new_page_node,
816 (unsigned long)pm);
817 else
818 err = -ENOENT;
820 up_read(&mm->mmap_sem);
821 return err;
822 }
824 /*
825 * Determine the nodes of a list of pages. The addr in the pm array
826 * must have been set to the virtual address of which we want to determine
827 * the node number.
828 */
829 static int do_pages_stat(struct mm_struct *mm, struct page_to_node *pm)
830 {
831 down_read(&mm->mmap_sem);
833 for ( ; pm->node != MAX_NUMNODES; pm++) {
834 struct vm_area_struct *vma;
835 struct page *page;
836 int err;
838 err = -EFAULT;
839 vma = find_vma(mm, pm->addr);
840 if (!vma)
841 goto set_status;
843 page = follow_page(vma, pm->addr, 0);
844 err = -ENOENT;
845 /* Use PageReserved to check for zero page */
846 if (!page || PageReserved(page))
847 goto set_status;
849 err = page_to_nid(page);
850 set_status:
851 pm->status = err;
852 }
854 up_read(&mm->mmap_sem);
855 return 0;
856 }
858 /*
859 * Move a list of pages in the address space of the currently executing
860 * process.
861 */
862 asmlinkage long sys_move_pages(pid_t pid, unsigned long nr_pages,
863 const void __user * __user *pages,
864 const int __user *nodes,
865 int __user *status, int flags)
866 {
867 int err = 0;
868 int i;
869 struct task_struct *task;
870 nodemask_t task_nodes;
871 struct mm_struct *mm;
872 struct page_to_node *pm = NULL;
874 /* Check flags */
875 if (flags & ~(MPOL_MF_MOVE|MPOL_MF_MOVE_ALL))
876 return -EINVAL;
878 if ((flags & MPOL_MF_MOVE_ALL) && !capable(CAP_SYS_NICE))
879 return -EPERM;
881 /* Find the mm_struct */
882 read_lock(&tasklist_lock);
883 task = pid ? find_task_by_pid(pid) : current;
884 if (!task) {
885 read_unlock(&tasklist_lock);
886 return -ESRCH;
887 }
888 mm = get_task_mm(task);
889 read_unlock(&tasklist_lock);
891 if (!mm)
892 return -EINVAL;
894 /*
895 * Check if this process has the right to modify the specified
896 * process. The right exists if the process has administrative
897 * capabilities, superuser privileges or the same
898 * userid as the target process.
899 */
900 if ((current->euid != task->suid) && (current->euid != task->uid) &&
901 (current->uid != task->suid) && (current->uid != task->uid) &&
902 !capable(CAP_SYS_NICE)) {
903 err = -EPERM;
904 goto out2;
905 }
907 err = security_task_movememory(task);
908 if (err)
909 goto out2;
912 task_nodes = cpuset_mems_allowed(task);
914 /* Limit nr_pages so that the multiplication may not overflow */
915 if (nr_pages >= ULONG_MAX / sizeof(struct page_to_node) - 1) {
916 err = -E2BIG;
917 goto out2;
918 }
920 pm = vmalloc((nr_pages + 1) * sizeof(struct page_to_node));
921 if (!pm) {
922 err = -ENOMEM;
923 goto out2;
924 }
926 /*
927 * Get parameters from user space and initialize the pm
928 * array. Return various errors if the user did something wrong.
929 */
930 for (i = 0; i < nr_pages; i++) {
931 const void *p;
933 err = -EFAULT;
934 if (get_user(p, pages + i))
935 goto out;
937 pm[i].addr = (unsigned long)p;
938 if (nodes) {
939 int node;
941 if (get_user(node, nodes + i))
942 goto out;
944 err = -ENODEV;
945 if (!node_online(node))
946 goto out;
948 err = -EACCES;
949 if (!node_isset(node, task_nodes))
950 goto out;
952 pm[i].node = node;
953 } else
954 pm[i].node = 0; /* anything to not match MAX_NUMNODES */
955 }
956 /* End marker */
957 pm[nr_pages].node = MAX_NUMNODES;
959 if (nodes)
960 err = do_move_pages(mm, pm, flags & MPOL_MF_MOVE_ALL);
961 else
962 err = do_pages_stat(mm, pm);
964 if (err >= 0)
965 /* Return status information */
966 for (i = 0; i < nr_pages; i++)
967 if (put_user(pm[i].status, status + i))
968 err = -EFAULT;
970 out:
971 vfree(pm);
972 out2:
973 mmput(mm);
974 return err;
975 }
976 #endif
978 /*
979 * Call migration functions in the vma_ops that may prepare
980 * memory in a vm for migration. migration functions may perform
981 * the migration for vmas that do not have an underlying page struct.
982 */
983 int migrate_vmas(struct mm_struct *mm, const nodemask_t *to,
984 const nodemask_t *from, unsigned long flags)
985 {
986 struct vm_area_struct *vma;
987 int err = 0;
989 for(vma = mm->mmap; vma->vm_next && !err; vma = vma->vm_next) {
990 if (vma->vm_ops && vma->vm_ops->migrate) {
991 err = vma->vm_ops->migrate(vma, to, from, flags);
992 if (err)
993 break;
994 }
995 }
996 return err;
997 }