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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3F144C433F5 for ; Wed, 2 Feb 2022 09:39:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S245521AbiBBJjA (ORCPT ); Wed, 2 Feb 2022 04:39:00 -0500 Received: from foss.arm.com ([217.140.110.172]:47022 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S244735AbiBBJi5 (ORCPT ); Wed, 2 Feb 2022 04:38:57 -0500 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id E7BA61FB; Wed, 2 Feb 2022 01:38:56 -0800 (PST) Received: from [10.163.43.221] (unknown [10.163.43.221]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 202483F40C; Wed, 2 Feb 2022 01:38:52 -0800 (PST) Subject: Re: [PATCH] mm: Merge pte_mkhuge() call into arch_make_huge_pte() To: Christophe Leroy , "linux-mm@kvack.org" Cc: Catalin Marinas , "linuxppc-dev@lists.ozlabs.org" , "linux-kernel@vger.kernel.org" , Paul Mackerras , "sparclinux@vger.kernel.org" , Andrew Morton , Will Deacon , "David S. Miller" , "linux-arm-kernel@lists.infradead.org" , Mike Kravetz References: <1643780286-18798-1-git-send-email-anshuman.khandual@arm.com> From: Anshuman Khandual Message-ID: <59ec5352-77eb-4c95-731e-100bcfa7003a@arm.com> Date: Wed, 2 Feb 2022 15:08:47 +0530 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2/2/22 11:50 AM, Christophe Leroy wrote: > > Le 02/02/2022 à 06:38, Anshuman Khandual a écrit : >> Each call into pte_mkhuge() is invariably followed by arch_make_huge_pte(). >> Instead arch_make_huge_pte() can accommodate pte_mkhuge() at the beginning. >> This updates generic fallback stub for arch_make_huge_pte() and available >> platforms definitions. This makes huge pte creation much cleaner and easier >> to follow. > I think it is a good cleanup. I always wonder why commit d9ed9faac283 > ("mm: add new arch_make_huge_pte() method for tile support") didn't move > the pte_mkhuge() into arch_make_huge_pte(). +1 > > When I implemented arch_make_huge_pte() for powerpc 8xx, in one case > arch_make_huge_pte() have to undo the things done by pte_mkhuge(), see below > > As a second step we could probably try to get rid of pte_mkhuge() > completely, at least in the core. Sure. > >> Cc: Catalin Marinas >> Cc: Will Deacon >> Cc: Michael Ellerman >> Cc: Paul Mackerras >> Cc: "David S. Miller" >> Cc: Mike Kravetz >> Cc: Andrew Morton >> Cc: linux-arm-kernel@lists.infradead.org >> Cc: linuxppc-dev@lists.ozlabs.org >> Cc: sparclinux@vger.kernel.org >> Cc: linux-mm@kvack.org >> Cc: linux-kernel@vger.kernel.org >> Signed-off-by: Anshuman Khandual > Reviewed-by: Christophe Leroy > >> --- >> arch/arm64/mm/hugetlbpage.c | 1 + >> arch/powerpc/include/asm/nohash/32/hugetlb-8xx.h | 1 + >> arch/sparc/mm/hugetlbpage.c | 1 + >> include/linux/hugetlb.h | 2 +- >> mm/hugetlb.c | 3 +-- >> mm/vmalloc.c | 1 - >> 6 files changed, 5 insertions(+), 4 deletions(-) >> >> diff --git a/arch/arm64/mm/hugetlbpage.c b/arch/arm64/mm/hugetlbpage.c >> index ffb9c229610a..228226c5fa80 100644 >> --- a/arch/arm64/mm/hugetlbpage.c >> +++ b/arch/arm64/mm/hugetlbpage.c >> @@ -347,6 +347,7 @@ pte_t arch_make_huge_pte(pte_t entry, unsigned int shift, vm_flags_t flags) >> { >> size_t pagesize = 1UL << shift; >> >> + entry = pte_mkhuge(entry); >> if (pagesize == CONT_PTE_SIZE) { >> entry = pte_mkcont(entry); >> } else if (pagesize == CONT_PMD_SIZE) { >> diff --git a/arch/powerpc/include/asm/nohash/32/hugetlb-8xx.h b/arch/powerpc/include/asm/nohash/32/hugetlb-8xx.h >> index 64b6c608eca4..e41e095158c7 100644 >> --- a/arch/powerpc/include/asm/nohash/32/hugetlb-8xx.h >> +++ b/arch/powerpc/include/asm/nohash/32/hugetlb-8xx.h >> @@ -70,6 +70,7 @@ static inline pte_t arch_make_huge_pte(pte_t entry, unsigned int shift, vm_flags >> { >> size_t size = 1UL << shift; >> >> + entry = pte_mkhuge(entry); > Could drop that and replace the below by: > > if (size == SZ_16K) > return __pte(pte_val(entry) | _PAGE_SPS); > else > return __pte(pte_val(entry) | _PAGE_SPS | _PAGE_HUGE); > > Sure, will change as stated above.