From patchwork Wed May 5 15:06:11 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Matthew Wilcox X-Patchwork-Id: 12240809 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=-18.8 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,SPF_PASS,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 44D63C433ED for ; Wed, 5 May 2021 17:57:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 16027613C3 for ; Wed, 5 May 2021 17:57:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234017AbhEER6j (ORCPT ); Wed, 5 May 2021 13:58:39 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55590 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233946AbhEER6X (ORCPT ); Wed, 5 May 2021 13:58:23 -0400 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 19D74C061761; Wed, 5 May 2021 10:30:58 -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=Av+BBOZUAh68SU/Va2q2cjv/1CjK/OveGHjToGYH/sA=; b=CAhWDKDx3yaZWJa35M23tD+lyu hmnqg3FWgFypWHnHGXbtRsbNfwwMFBsEOR/Ia8sjH8WdFRgIp4dbulaQePJRXCjYinBib8vdqlMGk Mjm449KWodW2lo9JTmys2AGZADpeTzgg6MGh28a9izlEcmPG2AGDUeFNvvJaeTBUeLcKpJ4eTtKYl nWIRDq2K07Nl3JGewOy1BM6J3qCMy187DbWBUWjGuX+grtj9gmOnpwUJr26rrIhJYByEbh6T6vqz/ 5JH/EPLSMuU4OtMxfC4gq+WMu41SHQZXDWUO6ell1IaTOHfmipJcFkhFmaInJQKrfEmD4Ej9T3Jjx /XgTs/ew==; Received: from willy by casper.infradead.org with local (Exim 4.94 #2 (Red Hat Linux)) id 1leKvk-000ceS-O0; Wed, 05 May 2021 17:04:11 +0000 From: "Matthew Wilcox (Oracle)" To: linux-fsdevel@vger.kernel.org, linux-mm@kvack.org Cc: "Matthew Wilcox (Oracle)" , linux-kernel@vger.kernel.org Subject: [PATCH v9 79/96] mm/filemap: Convert mapping_get_entry to return a folio Date: Wed, 5 May 2021 16:06:11 +0100 Message-Id: <20210505150628.111735-80-willy@infradead.org> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20210505150628.111735-1-willy@infradead.org> References: <20210505150628.111735-1-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) --- mm/filemap.c | 33 +++++++++++++++++---------------- 1 file changed, 17 insertions(+), 16 deletions(-) diff --git a/mm/filemap.c b/mm/filemap.c index 062610ae95d8..b3714dddb045 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -1732,34 +1732,33 @@ 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 (!page_cache_get_speculative(&folio->page)) goto repeat; /* @@ -1767,14 +1766,14 @@ static struct page *mapping_get_entry(struct address_space *mapping, * 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; } /** @@ -1814,10 +1813,12 @@ 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;