From patchwork Mon Jul 12 19:01:44 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Matthew Wilcox X-Patchwork-Id: 12371943 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=-16.6 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,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 B4331C07E9A for ; Mon, 12 Jul 2021 19:09:55 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 710EE60E08 for ; Mon, 12 Jul 2021 19:09:55 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 710EE60E08 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 87FC46B0073; Mon, 12 Jul 2021 15:09:55 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 82FC76B0096; Mon, 12 Jul 2021 15:09:55 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 6A82C6B0098; Mon, 12 Jul 2021 15:09:55 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0177.hostedemail.com [216.40.44.177]) by kanga.kvack.org (Postfix) with ESMTP id 416BC6B0073 for ; Mon, 12 Jul 2021 15:09:55 -0400 (EDT) Received: from smtpin07.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with ESMTP id 58275184E6 for ; Mon, 12 Jul 2021 19:09:54 +0000 (UTC) X-FDA: 78354875508.07.0730EDA Received: from casper.infradead.org (casper.infradead.org [90.155.50.34]) by imf09.hostedemail.com (Postfix) with ESMTP id 133183000108 for ; Mon, 12 Jul 2021 19:09:53 +0000 (UTC) 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=RSpBqEzRg+SMLcv/y8kgE4FOO3vbcCIE8BAtX0wLrTY=; b=bernQSkQuq6XEXpzpRdwC1AwEm VcXwLZuEOp4yYVQxmSrHnyzhHa/DRjc7Ey2pkxNTQc3yiw19EJNtoBvij4JRudnS7qQe0dsSUCSzn 7cR9sYaVYe3GVzP5t4kiA7LXKS3voe88+G2kfHkclocfdWfmNlQoVu+z5RIJ84g2PVKWoYGDL0KXU W6CyJEixUSKgrpEDJTpDXGPsF+pEHpKkcHEs/uDS5FRdIB/dB3i3zHaCyDdgbdcvJARiHv9XSqlG7 PaAEWGUuTIr9YbyTdspxjuICs2bxSJLyZE4aHzBP/QN6Y6mQG1Cz+aQb2oLYIQk4qbzSCikdVunME pS3kyf5A==; Received: from willy by casper.infradead.org with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1m31Hc-000Lbn-Cf; Mon, 12 Jul 2021 19:08:17 +0000 From: "Matthew Wilcox (Oracle)" To: akpm@linux-foundation.org Cc: "Matthew Wilcox (Oracle)" , linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, Christoph Hellwig , Jeff Layton , "Kirill A . Shutemov" , Vlastimil Babka , William Kucharski , David Howells Subject: [PATCH v13 12/32] mm: Handle per-folio private data Date: Mon, 12 Jul 2021 20:01:44 +0100 Message-Id: <20210712190204.80979-13-willy@infradead.org> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20210712190204.80979-1-willy@infradead.org> References: <20210712190204.80979-1-willy@infradead.org> MIME-Version: 1.0 X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: 133183000108 X-Stat-Signature: hj333533frupnerp5e3mhdnbzdw65675 Authentication-Results: imf09.hostedemail.com; dkim=pass header.d=infradead.org header.s=casper.20170209 header.b=bernQSkQ; dmarc=none; spf=none (imf09.hostedemail.com: domain of willy@infradead.org has no SPF policy when checking 90.155.50.34) smtp.mailfrom=willy@infradead.org X-HE-Tag: 1626116993-373208 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: Add folio_get_private() which mirrors 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 folio_attach_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 813 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) Reviewed-by: Christoph Hellwig Acked-by: Jeff Layton Acked-by: Kirill A. Shutemov Acked-by: Vlastimil Babka Reviewed-by: William Kucharski Reviewed-by: David Howells --- include/linux/mm_types.h | 11 +++++++++ include/linux/pagemap.h | 48 ++++++++++++++++++++++++---------------- 2 files changed, 40 insertions(+), 19 deletions(-) diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h index 7a11b25cf50f..c15b4af8ef4d 100644 --- a/include/linux/mm_types.h +++ b/include/linux/mm_types.h @@ -309,6 +309,12 @@ 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) @@ -316,6 +322,11 @@ static inline void set_page_private(struct page *page, unsigned long private) page->private = private; } +static inline void *folio_get_private(struct folio *folio) +{ + return folio->private; +} + 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 db1726b1bc1c..df18df0ab01b 100644 --- a/include/linux/pagemap.h +++ b/include/linux/pagemap.h @@ -184,42 +184,52 @@ static inline bool page_cache_get_speculative(struct page *page) } /** - * attach_page_private - Attach private data to a page. - * @page: Page to attach data to. - * @data: Data to attach to page. + * folio_attach_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 folio_attach_private(struct folio *folio, void *data) { - get_page(page); - set_page_private(page, (unsigned long)data); - SetPagePrivate(page); + folio_get(folio); + folio->private = data; + folio_set_private_flag(folio); } /** - * detach_page_private - Detach private data from a page. - * @page: Page to detach data from. + * folio_detach_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 *folio_detach_private(struct folio *folio) { - void *data = (void *)page_private(page); + void *data = folio_get_private(folio); - if (!PagePrivate(page)) + if (!folio_private(folio)) return NULL; - ClearPagePrivate(page); - set_page_private(page, 0); - put_page(page); + folio_clear_private_flag(folio); + folio->private = NULL; + folio_put(folio); return data; } +static inline void attach_page_private(struct page *page, void *data) +{ + folio_attach_private(page_folio(page), data); +} + +static inline void *detach_page_private(struct page *page) +{ + return folio_detach_private(page_folio(page)); +} + #ifdef CONFIG_NUMA extern struct page *__page_cache_alloc(gfp_t gfp); #else