diff options
| -rw-r--r-- | mm/Kconfig | 4 | ||||
| -rw-r--r-- | mm/migrate.c | 53 |
2 files changed, 23 insertions, 34 deletions
@@ -138,8 +138,8 @@ config SPLIT_PTLOCK_CPUS # config MIGRATION bool "Page migration" - def_bool y if NUMA - depends on SWAP && NUMA + def_bool y + depends on NUMA help Allows the migration of the physical location of pages of processes while the virtual addresses are not changed. This is useful for diff --git a/mm/migrate.c b/mm/migrate.c index 81721a0..8f91463 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -254,14 +254,20 @@ static int migrate_page_move_mapping(struct address_space *mapping, { struct page **radix_pointer; + if (!mapping) { + /* Anonymous page */ + if (page_count(page) != 1) + return -EAGAIN; + return 0; + } + write_lock_irq(&mapping->tree_lock); radix_pointer = (struct page **)radix_tree_lookup_slot( &mapping->page_tree, page_index(page)); - if (!page_mapping(page) || - page_count(page) != 2 + !!PagePrivate(page) || + if (page_count(page) != 2 + !!PagePrivate(page) || *radix_pointer != page) { write_unlock_irq(&mapping->tree_lock); return -EAGAIN; @@ -271,10 +277,12 @@ static int migrate_page_move_mapping(struct address_space *mapping, * Now we know that no one else is looking at the page. */ get_page(newpage); +#ifdef CONFIG_SWAP if (PageSwapCache(page)) { SetPageSwapCache(newpage); set_page_private(newpage, page_private(page)); } +#endif *radix_pointer = newpage; __put_page(page); @@ -308,7 +316,9 @@ static void migrate_page_copy(struct page *newpage, struct page *page) set_page_dirty(newpage); } +#ifdef CONFIG_SWAP ClearPageSwapCache(page); +#endif ClearPageActive(page); ClearPagePrivate(page); set_page_private(page, 0); @@ -353,16 +363,6 @@ int migrate_page(struct address_space *mapping, return rc; migrate_page_copy(newpage, page); - - /* - * Remove auxiliary swap entries and replace - * them with real ptes. - * - * Note that a real pte entry will allow processes that are not - * waiting on the page lock to use the new page via the page tables - * before the new page is unlocked. - */ - remove_from_swap(newpage); return 0; } EXPORT_SYMBOL(migrate_page); @@ -530,23 +530,7 @@ redo: goto unlock_page; /* - * 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. + * Establish migration ptes or remove ptes */ rc = -EPERM; if (try_to_unmap(page, 1) == SWAP_FAIL) @@ -569,9 +553,9 @@ redo: */ mapping = page_mapping(page); if (!mapping) - goto unlock_both; + rc = migrate_page(mapping, newpage, page); - if (mapping->a_ops->migratepage) + else if (mapping->a_ops->migratepage) /* * Most pages have a mapping and most filesystems * should provide a migration function. Anonymous @@ -584,10 +568,15 @@ redo: else rc = fallback_migrate_page(mapping, newpage, page); -unlock_both: + if (!rc) + remove_migration_ptes(page, newpage); + unlock_page(newpage); unlock_page: + if (rc) + remove_migration_ptes(page, page); + unlock_page(page); next: |
