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=-0.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,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 7B58DC55191 for ; Sun, 26 Apr 2020 03:01:29 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 3231420767 for ; Sun, 26 Apr 2020 03:01:29 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="UVpTWp7E" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 3231420767 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=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id B86458E0005; Sat, 25 Apr 2020 23:01:28 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id B366E8E0003; Sat, 25 Apr 2020 23:01:28 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id A4D928E0005; Sat, 25 Apr 2020 23:01:28 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0080.hostedemail.com [216.40.44.80]) by kanga.kvack.org (Postfix) with ESMTP id 8DF298E0003 for ; Sat, 25 Apr 2020 23:01:28 -0400 (EDT) Received: from smtpin12.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with ESMTP id 4BA53181AC9CC for ; Sun, 26 Apr 2020 03:01:28 +0000 (UTC) X-FDA: 76748505456.12.hat50_ccbce7b41523 X-HE-Tag: hat50_ccbce7b41523 X-Filterd-Recvd-Size: 5475 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by imf36.hostedemail.com (Postfix) with ESMTP for ; Sun, 26 Apr 2020 03:01:27 +0000 (UTC) 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 Cc: linux-mm@kvack.org, Russell King , Catalin Marinas , Will Deacon , Tony Luck , Fenghua Yu , Thomas Bogendoerfer , "James E.J. Bottomley" , Helge Deller , Benjamin Herrenschmidt , Paul Mackerras , Michael Ellerman , Paul Walmsley , Palmer Dabbelt , Heiko Carstens , Vasily Gorbik , Christian Borntraeger , Yoshinori Sato , Rich Felker , "David S. Miller" , Thomas Gleixner , Ingo Molnar , Borislav Petkov , "H. Peter Anvin" , Mike Kravetz , x86@kernel.org, linux-arm-kernel@lists.infradead.org, linux-ia64@vger.kernel.org, linux-mips@vger.kernel.org, linux-parisc@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-riscv@lists.infradead.org, linux-s390@vger.kernel.org, linux-sh@vger.kernel.org, sparclinux@vger.kernel.org, linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org 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-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: 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.