From patchwork Wed Mar 31 18:47:08 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Matthew Wilcox X-Patchwork-Id: 12175973 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,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 E910BC433ED for ; Wed, 31 Mar 2021 18:49:46 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 6FA7D61007 for ; Wed, 31 Mar 2021 18:49:46 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 6FA7D61007 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 08D746B0098; Wed, 31 Mar 2021 14:49:46 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 028706B0099; Wed, 31 Mar 2021 14:49:45 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id DE6266B009A; Wed, 31 Mar 2021 14:49:45 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0138.hostedemail.com [216.40.44.138]) by kanga.kvack.org (Postfix) with ESMTP id C103D6B0098 for ; Wed, 31 Mar 2021 14:49:45 -0400 (EDT) Received: from smtpin21.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id 829B1824999B for ; Wed, 31 Mar 2021 18:49:45 +0000 (UTC) X-FDA: 77981058330.21.BD9E8D6 Received: from casper.infradead.org (casper.infradead.org [90.155.50.34]) by imf30.hostedemail.com (Postfix) with ESMTP id DB432E0011D9 for ; Wed, 31 Mar 2021 18:49:43 +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=NRhqeoCoYorlNSPG0N+pti1euHQChgqgzhBAKtD+lGw=; b=qFujYRbdn8eqS9ULraOEPorrtH eXXN0qIaFqlNVwTQgyxNnH1ZphOCeS41ccbdJGiUNLdPBIEI+4P1ZtWq/EO/6rJsMn4ss7ZcSBIss SRnH9W0DsUAWdUVvOP7p+In9NBpc1XJffc1Ttfa/xiy6BY6GR/k4eE4M2ez+feY2TYXGGe8fv6LZo VLTMQVcArA2qxXXqMYC0ZQfkMhPLHi68ImuonYkwJ4WvNrIVTqeIDHLALbwnIJkBtN/TJezc4Wnb1 r3wA+c2Be2DyQzZuJoxli9s2EEdW80V0Yer4UHxWsOmhLQPm2mbxKpiEZPJexIcfOmS/K4ZfXUHZM 3CHEDOfg==; Received: from willy by casper.infradead.org with local (Exim 4.94 #2 (Red Hat Linux)) id 1lRfty-004zF2-Hb; Wed, 31 Mar 2021 18:49:16 +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, Zi Yan Subject: [PATCH v6 07/27] mm: Add get_folio Date: Wed, 31 Mar 2021 19:47:08 +0100 Message-Id: <20210331184728.1188084-8-willy@infradead.org> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20210331184728.1188084-1-willy@infradead.org> References: <20210331184728.1188084-1-willy@infradead.org> MIME-Version: 1.0 X-Rspamd-Queue-Id: DB432E0011D9 X-Stat-Signature: os5nrtgo5uymwit5xh47pgh16n3e4uhu X-Rspamd-Server: rspam02 Received-SPF: none (infradead.org>: No applicable sender policy available) receiver=imf30; identity=mailfrom; envelope-from=""; helo=casper.infradead.org; client-ip=90.155.50.34 X-HE-DKIM-Result: pass/pass X-HE-Tag: 1617216583-746850 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: If we know we have a folio, we can call get_folio() instead of get_page() and save the overhead of calling compound_head(). Signed-off-by: Matthew Wilcox (Oracle) Reviewed-by: Zi Yan Reviewed-by: Christoph Hellwig --- include/linux/mm.h | 26 +++++++++++++++++--------- 1 file changed, 17 insertions(+), 9 deletions(-) diff --git a/include/linux/mm.h b/include/linux/mm.h index 824acedc1253..818010a6b4c9 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -1205,18 +1205,26 @@ static inline bool is_pci_p2pdma_page(const struct page *page) } /* 127: arbitrary random number, small enough to assemble well */ -#define page_ref_zero_or_close_to_overflow(page) \ - ((unsigned int) page_ref_count(page) + 127u <= 127u) +#define folio_ref_zero_or_close_to_overflow(folio) \ + ((unsigned int) folio_ref_count(folio) + 127u <= 127u) + +/** + * get_folio - Increment the reference count on a folio. + * @folio: The folio. + * + * Context: May be called in any context, as long as you know that + * you have a refcount on the folio. If you do not already have one, + * try_grab_page() may be the right interface for you to use. + */ +static inline void get_folio(struct folio *folio) +{ + VM_BUG_ON_FOLIO(folio_ref_zero_or_close_to_overflow(folio), folio); + folio_ref_inc(folio); +} static inline void get_page(struct page *page) { - page = compound_head(page); - /* - * Getting a normal page or the head of a compound page - * requires to already have an elevated page->_refcount. - */ - VM_BUG_ON_PAGE(page_ref_zero_or_close_to_overflow(page), page); - page_ref_inc(page); + get_folio(page_folio(page)); } bool __must_check try_grab_page(struct page *page, unsigned int flags);