From patchwork Tue Jun 22 12:15:49 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Matthew Wilcox X-Patchwork-Id: 12337379 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-18.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0E113C2B9F4 for ; Tue, 22 Jun 2021 12:55:28 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id EB5F56113E for ; Tue, 22 Jun 2021 12:55:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231899AbhFVM5m (ORCPT ); Tue, 22 Jun 2021 08:57:42 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52292 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231315AbhFVM5l (ORCPT ); Tue, 22 Jun 2021 08:57:41 -0400 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3171DC061574; Tue, 22 Jun 2021 05:55:26 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=Content-Transfer-Encoding:MIME-Version: References:In-Reply-To:Message-Id:Date:Subject:Cc:To:From:Sender:Reply-To: Content-Type:Content-ID:Content-Description; bh=Y0KiXdMi6qlFopeP6+ne5fm8oMGgTCLjazxpZLPk4Hk=; b=UTZ71SvYXAe9/3lIFDELLAwucW TkEeC+tzX441Wo3DqtLi7uFp4Amj1t1PiRFn0QRtzKOKiGS9DJWTHiP1ZemeTnE/8goOqyuA5Fi/P Xxb//Pom+NSBjVg7W8KZLPl6nN5JKl5Ig3d+2ieUBMt4n+gyQywhacwxFK+ZbLFdLRGPFL5Twckez 98IabqlfgaXh/COj2Xm+UX84bT8sNzrGf/BFXCC7uqy9+q5oNF7ssGEwEI4ALCMYAFAtUiXT3JkAi xHGS6U6qPwKHdWh2pkjWLqGG+21v44iNhuLg91G25Mv7XNWfRxu8bD7kVqvFJJGUaf6PW+pYeHO1Y P0Zp7uOA==; Received: from willy by casper.infradead.org with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1lvfvC-00EJ75-T9; Tue, 22 Jun 2021 12:54:39 +0000 From: "Matthew Wilcox (Oracle)" To: akpm@linux-foundation.org Cc: "Matthew Wilcox (Oracle)" , linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: [PATCH v2 44/46] mm/filemap: Convert mapping_get_entry to return a folio Date: Tue, 22 Jun 2021 13:15:49 +0100 Message-Id: <20210622121551.3398730-45-willy@infradead.org> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20210622121551.3398730-1-willy@infradead.org> References: <20210622121551.3398730-1-willy@infradead.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org The pagecache only contains folios, so indicate that this is definitely not a tail page. Shrinks mapping_get_entry() by 56 bytes, but grows pagecache_get_page() by 21 bytes as gcc makes slightly different hot/cold code decisions. A net reduction of 35 bytes of text. Signed-off-by: Matthew Wilcox (Oracle) Reviewed-by: Christoph Hellwig --- mm/filemap.c | 38 +++++++++++++++++--------------------- 1 file changed, 17 insertions(+), 21 deletions(-) diff --git a/mm/filemap.c b/mm/filemap.c index a174f8ce87ea..7d0b51f30223 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -1754,49 +1754,43 @@ EXPORT_SYMBOL(page_cache_prev_miss); * @mapping: the address_space to search * @index: The page cache index. * - * Looks up the page cache slot at @mapping & @index. If there is a - * page cache page, the head page is returned with an increased refcount. + * Looks up the page cache entry at @mapping & @index. If it is a folio, + * it is returned with an increased refcount. If it is a shadow entry + * of a previously evicted folio, or a swap entry from shmem/tmpfs, + * it is returned without further action. * - * If the slot holds a shadow entry of a previously evicted page, or a - * swap entry from shmem/tmpfs, it is returned. - * - * Return: The head page or shadow entry, %NULL if nothing is found. + * Return: The folio, swap or shadow entry, %NULL if nothing is found. */ -static struct page *mapping_get_entry(struct address_space *mapping, +static struct folio *mapping_get_entry(struct address_space *mapping, pgoff_t index) { XA_STATE(xas, &mapping->i_pages, index); - struct page *page; + struct folio *folio; rcu_read_lock(); repeat: xas_reset(&xas); - page = xas_load(&xas); - if (xas_retry(&xas, page)) + folio = xas_load(&xas); + if (xas_retry(&xas, folio)) goto repeat; /* * A shadow entry of a recently evicted page, or a swap entry from * shmem/tmpfs. Return it without attempting to raise page count. */ - if (!page || xa_is_value(page)) + if (!folio || xa_is_value(folio)) goto out; - if (!page_cache_get_speculative(page)) + if (!folio_try_get_rcu(folio)) goto repeat; - /* - * Has the page moved or been split? - * This is part of the lockless pagecache protocol. See - * include/linux/pagemap.h for details. - */ - if (unlikely(page != xas_reload(&xas))) { - put_page(page); + if (unlikely(folio != xas_reload(&xas))) { + folio_put(folio); goto repeat; } out: rcu_read_unlock(); - return page; + return folio; } /** @@ -1836,10 +1830,12 @@ static struct page *mapping_get_entry(struct address_space *mapping, struct page *pagecache_get_page(struct address_space *mapping, pgoff_t index, int fgp_flags, gfp_t gfp_mask) { + struct folio *folio; struct page *page; repeat: - page = mapping_get_entry(mapping, index); + folio = mapping_get_entry(mapping, index); + page = &folio->page; if (xa_is_value(page)) { if (fgp_flags & FGP_ENTRY) return page;