From patchwork Sat Mar 20 05:40:48 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Matthew Wilcox X-Patchwork-Id: 12152267 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 D6059C433E9 for ; Sat, 20 Mar 2021 05:43:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B057261999 for ; Sat, 20 Mar 2021 05:43:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230053AbhCTFnG (ORCPT ); Sat, 20 Mar 2021 01:43:06 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54016 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229984AbhCTFmh (ORCPT ); Sat, 20 Mar 2021 01:42:37 -0400 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2301BC061762; Fri, 19 Mar 2021 22:42:37 -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=IP6QZgGwEXaaFopeekBczSGdfJmZJVj0NuzgQhtzlmA=; b=cMOvj2OzXkJGXJg/q/R+ZqybO2 trLn8Yg+taRequdAFhoxcXYNK/9teYoprdMTru8pqwzM9g8uSYXbL9D1nj33IkOHDAB4/0ajLNZ1F ZXLL6e+S4vIz5lisbxuBwXh6dHzt54g2p2wEZGHkoDYf8sfpkU0nDaNVheh3ktLS1wo2SycgHVsW7 6cNjq5pz2mgAANBgEuw3u2GMuD5ChgX6paFd3VlDScnH7G+8TU7pyipGBrCYOEbhqlhjLFFSlJ9FI dKRkduoNnWOtlU6pkBuJDpvnQKWNnX9gz7uKVtLzj7TvMH37y5XWAEjAJ4olzXv0cZ9G4BhV7LvYt rudyYfBg==; Received: from willy by casper.infradead.org with local (Exim 4.94 #2 (Red Hat Linux)) id 1lNUNU-005SY1-G5; Sat, 20 Mar 2021 05:42:25 +0000 From: "Matthew Wilcox (Oracle)" To: linux-mm@kvack.org Cc: "Matthew Wilcox (Oracle)" , linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-cachefs@redhat.com, linux-afs@lists.infradead.org Subject: [PATCH v5 11/27] mm: Handle per-folio private data Date: Sat, 20 Mar 2021 05:40:48 +0000 Message-Id: <20210320054104.1300774-12-willy@infradead.org> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20210320054104.1300774-1-willy@infradead.org> References: <20210320054104.1300774-1-willy@infradead.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org Add folio_private() and set_folio_private() which mirror page_private() and set_page_private() -- ie folio private data is the same as page private data. The only difference is that these return a void * instead of an unsigned long, which matches the majority of users. Turn attach_page_private() into attach_folio_private() and reimplement attach_page_private() as a wrapper. No filesystem which uses page private data currently supports compound pages, so we're free to define the rules. attach_page_private() may only be called on a head page; if you want to add private data to a tail page, you can call set_page_private() directly (and shouldn't increment the page refcount! That should be done when adding private data to the head page / folio). This saves 597 bytes of text with the distro-derived config that I'm testing due to removing the calls to compound_head() in get_page() & put_page(). Signed-off-by: Matthew Wilcox (Oracle) --- include/linux/mm_types.h | 16 ++++++++++++++ include/linux/pagemap.h | 48 ++++++++++++++++++++++++---------------- 2 files changed, 45 insertions(+), 19 deletions(-) diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h index 4fc0b230d3ea..90086f93e9de 100644 --- a/include/linux/mm_types.h +++ b/include/linux/mm_types.h @@ -278,6 +278,12 @@ static inline atomic_t *compound_pincount_ptr(struct page *page) #define PAGE_FRAG_CACHE_MAX_SIZE __ALIGN_MASK(32768, ~PAGE_MASK) #define PAGE_FRAG_CACHE_MAX_ORDER get_order(PAGE_FRAG_CACHE_MAX_SIZE) +/* + * page_private can be used on tail pages. However, PagePrivate is only + * checked by the VM on the head page. So page_private on the tail pages + * should be used for data that's ancillary to the head page (eg attaching + * buffer heads to tail pages after attaching buffer heads to the head page) + */ #define page_private(page) ((page)->private) static inline void set_page_private(struct page *page, unsigned long private) @@ -285,6 +291,16 @@ static inline void set_page_private(struct page *page, unsigned long private) page->private = private; } +static inline void *folio_private(struct folio *folio) +{ + return (void *)folio->page.private; +} + +static inline void set_folio_private(struct folio *folio, void *v) +{ + folio->page.private = (unsigned long)v; +} + struct page_frag_cache { void * va; #if (PAGE_SIZE < PAGE_FRAG_CACHE_MAX_SIZE) diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h index 8c844ba67785..6676210addf6 100644 --- a/include/linux/pagemap.h +++ b/include/linux/pagemap.h @@ -260,42 +260,52 @@ static inline int page_cache_add_speculative(struct page *page, int count) } /** - * attach_page_private - Attach private data to a page. - * @page: Page to attach data to. - * @data: Data to attach to page. + * attach_folio_private - Attach private data to a folio. + * @folio: Folio to attach data to. + * @data: Data to attach to folio. * - * Attaching private data to a page increments the page's reference count. - * The data must be detached before the page will be freed. + * Attaching private data to a folio increments the page's reference count. + * The data must be detached before the folio will be freed. */ -static inline void attach_page_private(struct page *page, void *data) +static inline void attach_folio_private(struct folio *folio, void *data) { - get_page(page); - set_page_private(page, (unsigned long)data); - SetPagePrivate(page); + get_folio(folio); + set_folio_private(folio, data); + SetFolioPrivate(folio); } /** - * detach_page_private - Detach private data from a page. - * @page: Page to detach data from. + * detach_folio_private - Detach private data from a folio. + * @folio: Folio to detach data from. * - * Removes the data that was previously attached to the page and decrements + * Removes the data that was previously attached to the folio and decrements * the refcount on the page. * - * Return: Data that was attached to the page. + * Return: Data that was attached to the folio. */ -static inline void *detach_page_private(struct page *page) +static inline void *detach_folio_private(struct folio *folio) { - void *data = (void *)page_private(page); + void *data = folio_private(folio); - if (!PagePrivate(page)) + if (!FolioPrivate(folio)) return NULL; - ClearPagePrivate(page); - set_page_private(page, 0); - put_page(page); + ClearFolioPrivate(folio); + set_folio_private(folio, NULL); + put_folio(folio); return data; } +static inline void attach_page_private(struct page *page, void *data) +{ + attach_folio_private(page_folio(page), data); +} + +static inline void *detach_page_private(struct page *page) +{ + return detach_folio_private(page_folio(page)); +} + #ifdef CONFIG_NUMA extern struct page *__page_cache_alloc(gfp_t gfp); #else