From mboxrd@z Thu Jan 1 00:00:00 1970 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=-0.6 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no 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 00FB3C55185 for ; Sun, 26 Apr 2020 03:03:15 +0000 (UTC) Received: from lists.ozlabs.org (lists.ozlabs.org [203.11.71.2]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 54A4220724 for ; Sun, 26 Apr 2020 03:03:14 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="UVpTWp7E" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 54A4220724 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linux-foundation.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Received: from lists.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 498t5C6GyHzDqcN for ; Sun, 26 Apr 2020 13:03:11 +1000 (AEST) Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=linux-foundation.org (client-ip=198.145.29.99; helo=mail.kernel.org; envelope-from=akpm@linux-foundation.org; receiver=) Authentication-Results: lists.ozlabs.org; dmarc=none (p=none dis=none) header.from=linux-foundation.org Authentication-Results: lists.ozlabs.org; dkim=pass (1024-bit key; unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=default header.b=UVpTWp7E; dkim-atps=neutral Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 498t3G1NK9zDqQN for ; Sun, 26 Apr 2020 13:01:29 +1000 (AEST) Received: from localhost.localdomain (c-73-231-172-41.hsd1.ca.comcast.net [73.231.172.41]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 6969B206D4; Sun, 26 Apr 2020 03:01:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1587870086; bh=tCSwWc8iRTvfzhr9Bpi0vaaHrDRBHLwWGG3vKGlFHqg=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=UVpTWp7EJhgRsQXBhfo6AT4VrUdy1nNy8nOq/LfihYfu1NC4LJc05Iz8GAX1ZT5f3 axlF830cN9T/YdFik2zo+N3qO2F4mins96Mu5bgI3K/fB5ghL5mkLmCLUuWklYIKG9 HZl62/U2hyOlgj8km6aRA/b/nX2GmC3gaq8w7s7A= Date: Sat, 25 Apr 2020 20:01:24 -0700 From: Andrew Morton To: Anshuman Khandual Subject: Re: [PATCH 3/3] mm/hugetlb: Introduce HAVE_ARCH_CLEAR_HUGEPAGE_FLAGS Message-Id: <20200425200124.20d0c75fcaef05d062d3667c@linux-foundation.org> In-Reply-To: <87d37591-caa2-b82b-392a-3a29b2c7e9a6@arm.com> References: <1586864670-21799-1-git-send-email-anshuman.khandual@arm.com> <1586864670-21799-4-git-send-email-anshuman.khandual@arm.com> <20200425175511.7a68efb5e2f4436fe0328c1d@linux-foundation.org> <87d37591-caa2-b82b-392a-3a29b2c7e9a6@arm.com> X-Mailer: Sylpheed 3.5.1 (GTK+ 2.24.31; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Rich Felker , linux-ia64@vger.kernel.org, linux-sh@vger.kernel.org, Catalin Marinas , Heiko Carstens , linux-kernel@vger.kernel.org, "James E.J. Bottomley" , linux-mm@kvack.org, Paul Mackerras , "H. Peter Anvin" , sparclinux@vger.kernel.org, linux-riscv@lists.infradead.org, Will Deacon , linux-arch@vger.kernel.org, linux-s390@vger.kernel.org, Yoshinori Sato , Helge Deller , x86@kernel.org, Russell King , Christian Borntraeger , Ingo Molnar , Fenghua Yu , Vasily Gorbik , Thomas Bogendoerfer , Borislav Petkov , Paul Walmsley , Thomas Gleixner , linux-arm-kernel@lists.infradead.org, Tony Luck , linux-parisc@vger.kernel.org, linux-mips@vger.kernel.org, Palmer Dabbelt , linuxppc-dev@lists.ozlabs.org, "David S. Miller" , Mike Kravetz Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" On Sun, 26 Apr 2020 08:13:17 +0530 Anshuman Khandual wrote: > > > On 04/26/2020 06:25 AM, Andrew Morton wrote: > > On Tue, 14 Apr 2020 17:14:30 +0530 Anshuman Khandual wrote: > > > >> There are multiple similar definitions for arch_clear_hugepage_flags() on > >> various platforms. This introduces HAVE_ARCH_CLEAR_HUGEPAGE_FLAGS for those > >> platforms that need to define their own arch_clear_hugepage_flags() while > >> also providing a generic fallback definition for others to use. This help > >> reduce code duplication. > >> > >> ... > >> > >> --- a/include/linux/hugetlb.h > >> +++ b/include/linux/hugetlb.h > >> @@ -544,6 +544,10 @@ static inline int is_hugepage_only_range(struct mm_struct *mm, > >> } > >> #endif > >> > >> +#ifndef HAVE_ARCH_CLEAR_HUGEPAGE_FLAGS > >> +static inline void arch_clear_hugepage_flags(struct page *page) { } > >> +#endif > >> + > >> #ifndef arch_make_huge_pte > >> static inline pte_t arch_make_huge_pte(pte_t entry, struct vm_area_struct *vma, > >> struct page *page, int writable) > > > > This is the rather old-school way of doing it. The Linus-suggested way is > > > > #ifndef arch_clear_hugepage_flags > > static inline void arch_clear_hugepage_flags(struct page *page) > > { > > } > > #define arch_clear_hugepage_flags arch_clear_hugepage_flags > > Do we need that above line here ? Is not that implicit. It depends if other header files want to test whether arch_clear_hugepage_flags is already defined. If the header heorarchy is well-defined and working properly, they shouldn't need to, because we're reliably indluding the relevant arch header before (or early within) include/linux/hugetlb.h. It would be nice if #define arch_clear_hugepage_flags arch_clear_hugepage_flags #define arch_clear_hugepage_flags arch_clear_hugepage_flags were to generate an compiler error but it doesn't. If it did we could detect these incorrect inclusion orders. > > #endif > > > > And the various arch headers do > > > > static inline void arch_clear_hugepage_flags(struct page *page) > > { > > > > } > > #define arch_clear_hugepage_flags arch_clear_hugepage_flags > > > > It's a small difference - mainly to avoid adding two variables to the > > overall namespace where one would do. > > Understood, will change and resend. That's OK - I've queued up that fix.