diff options
| -rw-r--r-- | mm/migrate.c | 90 |
1 files changed, 39 insertions, 51 deletions
diff --git a/mm/migrate.c b/mm/migrate.c index f65e69d94527..5a340f4ca212 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -349,6 +349,42 @@ int buffer_migrate_page(struct address_space *mapping, } EXPORT_SYMBOL(buffer_migrate_page); +static int fallback_migrate_page(struct address_space *mapping, + struct page *newpage, struct page *page) +{ + /* + * Default handling if a filesystem does not provide + * a migration function. We can only migrate clean + * pages so try to write out any dirty pages first. + */ + if (PageDirty(page)) { + switch (pageout(page, mapping)) { + case PAGE_KEEP: + case PAGE_ACTIVATE: + return -EAGAIN; + + case PAGE_SUCCESS: + /* Relock since we lost the lock */ + lock_page(page); + /* Must retry since page state may have changed */ + return -EAGAIN; + + case PAGE_CLEAN: + ; /* try to migrate the page below */ + } + } + + /* + * Buffers may be managed in a filesystem specific way. + * We must have no buffers or drop them. + */ + if (page_has_buffers(page) && + !try_to_release_page(page, GFP_KERNEL)) + return -EAGAIN; + + return migrate_page(mapping, newpage, page); +} + /* * migrate_pages * @@ -478,7 +514,7 @@ redo: if (!mapping) goto unlock_both; - if (mapping->a_ops->migratepage) { + if (mapping->a_ops->migratepage) /* * Most pages have a mapping and most filesystems * should provide a migration function. Anonymous @@ -488,56 +524,8 @@ redo: */ rc = mapping->a_ops->migratepage(mapping, newpage, page); - goto unlock_both; - } - - /* - * Default handling if a filesystem does not provide - * a migration function. We can only migrate clean - * pages so try to write out any dirty pages first. - */ - if (PageDirty(page)) { - switch (pageout(page, mapping)) { - case PAGE_KEEP: - case PAGE_ACTIVATE: - goto unlock_both; - - case PAGE_SUCCESS: - unlock_page(newpage); - goto next; - - case PAGE_CLEAN: - ; /* try to migrate the page below */ - } - } - - /* - * Buffers are managed in a filesystem specific way. - * We must have no buffers or drop them. - */ - if (!page_has_buffers(page) || - try_to_release_page(page, GFP_KERNEL)) { - rc = migrate_page(mapping, newpage, page); - goto unlock_both; - } - - /* - * On early passes with mapped pages simply - * retry. There may be a lock held for some - * buffers that may go away. Later - * swap them out. - */ - if (pass > 4) { - /* - * Persistently unable to drop buffers..... As a - * measure of last resort we fall back to - * swap_page(). - */ - unlock_page(newpage); - newpage = NULL; - rc = swap_page(page); - goto next; - } + else + rc = fallback_migrate_page(mapping, newpage, page); unlock_both: unlock_page(newpage); |