From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Fri, 28 Apr 2006 20:23:22 -0700 (PDT) From: Christoph Lameter Message-Id: <20060429032322.4999.77950.sendpatchset@schroedinger.engr.sgi.com> In-Reply-To: <20060429032246.4999.21714.sendpatchset@schroedinger.engr.sgi.com> References: <20060429032246.4999.21714.sendpatchset@schroedinger.engr.sgi.com> Subject: [PATCH 7/7] PM cleanup: Move fallback handling into special function Sender: owner-linux-mm@kvack.org Return-Path: To: akpm@osdl.org Cc: linux-mm@kvack.org, Hugh Dickins , Lee Schermerhorn , Christoph Lameter , KAMEZAWA Hiroyuki List-ID: page migration: Add new fallback function Move the fallback code into a new fallback function and make the function behave like any other migration function. This requires retaking the lock if pageout() drops it. Signed-off-by: Christoph Lameter Index: linux-2.6.17-rc3/mm/migrate.c =================================================================== --- linux-2.6.17-rc3.orig/mm/migrate.c 2006-04-28 18:12:58.595320357 -0700 +++ linux-2.6.17-rc3/mm/migrate.c 2006-04-28 18:25:47.893218995 -0700 @@ -349,6 +349,42 @@ } 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 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)) + return -EAGAIN; + + return migrate_page(mapping, newpage, page); +} + /* * migrate_pages * @@ -478,7 +514,7 @@ 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 @@ */ 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); -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org