From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wr0-f200.google.com (mail-wr0-f200.google.com [209.85.128.200]) by kanga.kvack.org (Postfix) with ESMTP id 81EE56B0266 for ; Thu, 11 Jan 2018 08:06:10 -0500 (EST) Received: by mail-wr0-f200.google.com with SMTP id k2so1466657wrg.3 for ; Thu, 11 Jan 2018 05:06:10 -0800 (PST) Received: from relay5-d.mail.gandi.net (relay5-d.mail.gandi.net. [217.70.183.197]) by mx.google.com with ESMTPS id o27si465505wro.223.2018.01.11.05.06.08 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 11 Jan 2018 05:06:08 -0800 (PST) Subject: Re: [PATCH] mm, THP: vmf_insert_pfn_pud depends on CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD References: <1515660811-12293-1-git-send-email-aghiti@upmem.com> <20180111100620.GY1732@dhcp22.suse.cz> From: Alexandre Ghiti Message-ID: <71853228-0beb-1e69-df47-59fa1bc5bd2f@upmem.com> Date: Thu, 11 Jan 2018 14:05:34 +0100 MIME-Version: 1.0 In-Reply-To: <20180111100620.GY1732@dhcp22.suse.cz> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Content-Language: en-US Sender: owner-linux-mm@kvack.org List-ID: To: Michal Hocko Cc: linux-mm@kvack.org, akpm@linux-foundation.org, kirill.shutemov@linux.intel.com, dan.j.williams@intel.com, zi.yan@cs.rutgers.edu, gregkh@linuxfoundation.org, n-horiguchi@ah.jp.nec.com, willy@linux.intel.com, mark.rutland@arm.com, linux-kernel@vger.kernel.org On 11/01/2018 11:06, Michal Hocko wrote: > On Thu 11-01-18 09:53:31, Alexandre Ghiti wrote: >> The only definition of vmf_insert_pfn_pud depends on >> CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD being defined. Then its declaration in >> include/linux/huge_mm.h should have the same restriction so that we do >> not expose this function if CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD is >> not defined. > Why is this a problem? Compiler should simply throw away any > declarations which are not used? It is not a big problem but surrounding the declaration with the #ifdef makes the compilation of external modules fail with an "error: implicit declaration of function vmf_insert_pfn_pud" if CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD is not defined. I think it is cleaner than generating a .ko which would not load anyway. > >> Signed-off-by: Alexandre Ghiti >> --- >> include/linux/huge_mm.h | 2 ++ >> 1 file changed, 2 insertions(+) >> >> diff --git a/include/linux/huge_mm.h b/include/linux/huge_mm.h >> index a8a1262..11794f6a 100644 >> --- a/include/linux/huge_mm.h >> +++ b/include/linux/huge_mm.h >> @@ -48,8 +48,10 @@ extern int change_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd, >> int prot_numa); >> int vmf_insert_pfn_pmd(struct vm_area_struct *vma, unsigned long addr, >> pmd_t *pmd, pfn_t pfn, bool write); >> +#ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD >> int vmf_insert_pfn_pud(struct vm_area_struct *vma, unsigned long addr, >> pud_t *pud, pfn_t pfn, bool write); >> +#endif >> enum transparent_hugepage_flag { >> TRANSPARENT_HUGEPAGE_FLAG, >> TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, >> -- >> 2.1.4 >> -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org