diff options
| -rw-r--r-- | mm/migrate.c | 76 |
1 files changed, 31 insertions, 45 deletions
diff --git a/mm/migrate.c b/mm/migrate.c index 2803a6698dd..8095c607a49 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -166,15 +166,14 @@ retry: } /* - * Remove references for a page and establish the new page with the correct - * basic settings to be able to stop accesses to the page. + * Replace the page in the mapping. * * The number of remaining references must be: * 1 for anonymous pages without a mapping * 2 for pages with a mapping * 3 for pages with a mapping and PagePrivate set. */ -static int migrate_page_remove_references(struct page *newpage, +static int migrate_page_move_mapping(struct page *newpage, struct page *page) { struct address_space *mapping = page_mapping(page); @@ -183,35 +182,6 @@ static int migrate_page_remove_references(struct page *newpage, if (!mapping) return -EAGAIN; - /* - * Establish swap ptes for anonymous pages or destroy pte - * maps for files. - * - * In order to reestablish file backed mappings the fault handlers - * will take the radix tree_lock which may then be used to stop - * processses from accessing this page until the new page is ready. - * - * A process accessing via a swap pte (an anonymous page) will take a - * page_lock on the old page which will block the process until the - * migration attempt is complete. At that time the PageSwapCache bit - * will be examined. If the page was migrated then the PageSwapCache - * bit will be clear and the operation to retrieve the page will be - * retried which will find the new page in the radix tree. Then a new - * direct mapping may be generated based on the radix tree contents. - * - * If the page was not migrated then the PageSwapCache bit - * is still set and the operation may continue. - */ - if (try_to_unmap(page, 1) == SWAP_FAIL) - /* A vma has VM_LOCKED set -> permanent failure */ - return -EPERM; - - /* - * Give up if we were unable to remove all mappings. - */ - if (page_mapcount(page)) - return -EAGAIN; - write_lock_irq(&mapping->tree_lock); radix_pointer = (struct page **)radix_tree_lookup_slot( @@ -310,7 +280,7 @@ int migrate_page(struct page *newpage, struct page *page) BUG_ON(PageWriteback(page)); /* Writeback must be complete */ - rc = migrate_page_remove_references(newpage, page); + rc = migrate_page_move_mapping(newpage, page); if (rc) return rc; @@ -349,7 +319,7 @@ int buffer_migrate_page(struct page *newpage, struct page *page) head = page_buffers(page); - rc = migrate_page_remove_references(newpage, page); + rc = migrate_page_move_mapping(newpage, page); if (rc) return rc; @@ -482,6 +452,33 @@ redo: lock_page(newpage); /* + * Establish swap ptes for anonymous pages or destroy pte + * maps for files. + * + * In order to reestablish file backed mappings the fault handlers + * will take the radix tree_lock which may then be used to stop + * processses from accessing this page until the new page is ready. + * + * A process accessing via a swap pte (an anonymous page) will take a + * page_lock on the old page which will block the process until the + * migration attempt is complete. At that time the PageSwapCache bit + * will be examined. If the page was migrated then the PageSwapCache + * bit will be clear and the operation to retrieve the page will be + * retried which will find the new page in the radix tree. Then a new + * direct mapping may be generated based on the radix tree contents. + * + * If the page was not migrated then the PageSwapCache bit + * is still set and the operation may continue. + */ + rc = -EPERM; + if (try_to_unmap(page, 1) == SWAP_FAIL) + /* A vma has VM_LOCKED set -> permanent failure */ + goto unlock_both; + + rc = -EAGAIN; + if (page_mapped(page)) + goto unlock_both; + /* * Pages are properly locked and writeback is complete. * Try to migrate the page. */ @@ -501,17 +498,6 @@ redo: goto unlock_both; } - /* Make sure the dirty bit is up to date */ - if (try_to_unmap(page, 1) == SWAP_FAIL) { - rc = -EPERM; - goto unlock_both; - } - - if (page_mapcount(page)) { - rc = -EAGAIN; - goto unlock_both; - } - /* * Default handling if a filesystem does not provide * a migration function. We can only migrate clean |