Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756748AbXLRWAb (ORCPT ); Tue, 18 Dec 2007 17:00:31 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753483AbXLRWAV (ORCPT ); Tue, 18 Dec 2007 17:00:21 -0500 Received: from extu-mxob-2.symantec.com ([216.10.194.135]:59775 "EHLO extu-mxob-2.symantec.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753290AbXLRWAU (ORCPT ); Tue, 18 Dec 2007 17:00:20 -0500 Date: Tue, 18 Dec 2007 21:59:22 +0000 (GMT) From: Hugh Dickins X-X-Sender: hugh@blonde.wat.veritas.com To: Andrew Morton cc: Christoph Rohland , Nick Piggin , linux-kernel@vger.kernel.org Subject: [PATCH 2/9] tmpfs: shuffle add_to_swap_caches In-Reply-To: Message-ID: References: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4114 Lines: 121 add_to_swap_cache doesn't amount to much: merge it into its sole caller read_swap_cache_async. But we'll be needing to call __add_to_swap_cache from shmem.c, so promote it to the new add_to_swap_cache. Both were static, so there's no interface confusion to worry about. And lose that inappropriate "Anon pages are already on the LRU" comment in the merging: they're not already on the LRU, as Nick Piggin noticed. Signed-off-by: Hugh Dickins --- mm/swap_state.c | 53 ++++++++++++++++------------------------------ 1 file changed, 19 insertions(+), 34 deletions(-) --- tmpfs1/mm/swap_state.c 2007-12-05 16:42:16.000000000 +0000 +++ tmpfs2/mm/swap_state.c 2007-12-05 16:42:16.000000000 +0000 @@ -64,10 +64,10 @@ void show_swap_cache_info(void) } /* - * __add_to_swap_cache resembles add_to_page_cache on swapper_space, + * add_to_swap_cache resembles add_to_page_cache on swapper_space, * but sets SwapCache flag and private instead of mapping and index. */ -static int __add_to_swap_cache(struct page *page, swp_entry_t entry, +static int add_to_swap_cache(struct page *page, swp_entry_t entry, gfp_t gfp_mask) { int error; @@ -94,28 +94,6 @@ static int __add_to_swap_cache(struct pa return error; } -static int add_to_swap_cache(struct page *page, swp_entry_t entry, - gfp_t gfp_mask) -{ - int error; - - BUG_ON(PageLocked(page)); - if (!swap_duplicate(entry)) - return -ENOENT; - - SetPageLocked(page); - error = __add_to_swap_cache(page, entry, gfp_mask & GFP_KERNEL); - /* - * Anon pages are already on the LRU, we don't run lru_cache_add here. - */ - if (error) { - ClearPageLocked(page); - swap_free(entry); - return error; - } - return 0; -} - /* * This must be called only on pages that have * been verified to be in the swap cache. @@ -165,7 +143,7 @@ int add_to_swap(struct page * page, gfp_ /* * Add it to the swap cache and mark it dirty */ - err = __add_to_swap_cache(page, entry, + err = add_to_swap_cache(page, entry, gfp_mask|__GFP_NOMEMALLOC|__GFP_NOWARN); switch (err) { @@ -210,7 +188,7 @@ void delete_from_swap_cache(struct page */ int move_to_swap_cache(struct page *page, swp_entry_t entry) { - int err = __add_to_swap_cache(page, entry, GFP_ATOMIC); + int err = add_to_swap_cache(page, entry, GFP_ATOMIC); if (!err) { remove_from_page_cache(page); page_cache_release(page); /* pagecache ref */ @@ -335,16 +313,21 @@ struct page *read_swap_cache_async(swp_e } /* + * Swap entry may have been freed since our caller observed it. + */ + if (!swap_duplicate(entry)) + break; + + /* * Associate the page with swap entry in the swap cache. - * May fail (-ENOENT) if swap entry has been freed since - * our caller observed it. May fail (-EEXIST) if there - * is already a page associated with this entry in the - * swap cache: added by a racing read_swap_cache_async, - * or by try_to_swap_out (or shmem_writepage) re-using - * the just freed swap entry for an existing page. + * May fail (-EEXIST) if there is already a page associated + * with this entry in the swap cache: added by a racing + * read_swap_cache_async, or add_to_swap or shmem_writepage + * re-using the just freed swap entry for an existing page. * May fail (-ENOMEM) if radix-tree node allocation failed. */ - err = add_to_swap_cache(new_page, entry, gfp_mask); + SetPageLocked(new_page); + err = add_to_swap_cache(new_page, entry, gfp_mask & GFP_KERNEL); if (!err) { /* * Initiate read into locked page and return. @@ -353,7 +336,9 @@ struct page *read_swap_cache_async(swp_e swap_readpage(NULL, new_page); return new_page; } - } while (err != -ENOENT && err != -ENOMEM); + ClearPageLocked(new_page); + swap_free(entry); + } while (err != -ENOMEM); if (new_page) page_cache_release(new_page); -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/