From patchwork Sat Mar 20 05:40:46 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Matthew Wilcox X-Patchwork-Id: 12152265 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 620FBC433E2 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 3F7B96193E for ; Sat, 20 Mar 2021 05:43:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229990AbhCTFmh (ORCPT ); Sat, 20 Mar 2021 01:42:37 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53978 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229913AbhCTFm1 (ORCPT ); Sat, 20 Mar 2021 01:42:27 -0400 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C2F45C061762; Fri, 19 Mar 2021 22:42:26 -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=CaovRBaNkCVTqsYVernAM0LyxVJ2htiMQIZKuC/uIxU=; b=geYK0WL7vhEsxuUgyus013JvCI KdytovtU1KhVoFETd/G89E7koQ1cLjPXplAnZ2o2AImG+gIc4/Hp1veUSI9R+QxjO7T3YeILuaDNZ rOy3jB1cTcnRkWI57Da5itlUWLdYJ3gDz+7moeOpVPb4xB5oXCFeoSNU38RI6rTHeqnFx+fFeEDX3 8Z7uKIr+Jhnn7NSpt2b7ad66pVPDveEWZkhHKxRVebRq82lPyXjzqwhHM82n6Rk+D0lFAVbna4UFo 0VVmm8BS+MVs2Et6d7tez3AhvRCJ/eLepQ4xvkQibhkYyuq/guBciN6/O23haSJSZ9LHhpuEgPUK4 eiJANc+w==; Received: from willy by casper.infradead.org with local (Exim 4.94 #2 (Red Hat Linux)) id 1lNUNF-005SWa-Td; Sat, 20 Mar 2021 05:42:14 +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 v5 09/27] mm: Add get_folio Date: Sat, 20 Mar 2021 05:40:46 +0000 Message-Id: <20210320054104.1300774-10-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 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 --- 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 5052479febc7..8fc7b04a1438 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -1198,18 +1198,26 @@ 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) page_ref_count(&folio->page) + 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); + page_ref_inc(&folio->page); +} 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);