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 3C5A7C7EE31 for ; Wed, 1 Mar 2023 08:32:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229783AbjCAIc5 (ORCPT ); Wed, 1 Mar 2023 03:32:57 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60792 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229667AbjCAIcy (ORCPT ); Wed, 1 Mar 2023 03:32:54 -0500 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 065F21FE2; Wed, 1 Mar 2023 00:32:52 -0800 (PST) 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 7A9F72F4; Wed, 1 Mar 2023 00:33:35 -0800 (PST) Received: from [10.162.41.9] (unknown [10.162.41.9]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 71C0F3F99C; Wed, 1 Mar 2023 00:32:48 -0800 (PST) Message-ID: <10b92874-222a-6f4d-2542-092c5a5e72db@arm.com> Date: Wed, 1 Mar 2023 14:02:45 +0530 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.7.1 Subject: Re: [PATCH V2] mm: Merge pte_mkhuge() call into arch_make_huge_pte() Content-Language: en-US To: Christophe Leroy , "linux-mm@kvack.org" Cc: Catalin Marinas , Will Deacon , Michael Ellerman , Paul Mackerras , "David S. Miller" , Mike Kravetz , Andrew Morton , "linux-arm-kernel@lists.infradead.org" , "linuxppc-dev@lists.ozlabs.org" , "sparclinux@vger.kernel.org" , "linux-kernel@vger.kernel.org" References: <1643860669-26307-1-git-send-email-anshuman.khandual@arm.com> <1ea45095-0926-a56a-a273-816709e9075e@csgroup.eu> From: Anshuman Khandual In-Reply-To: <1ea45095-0926-a56a-a273-816709e9075e@csgroup.eu> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 3/1/23 12:26, Christophe Leroy wrote: > Hi, > > Le 03/02/2022 à 04:57, 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 can't remember, what was the reason for not doing it in > remove_migration_pte() as well ? > Looking at it, I have the feeling that we now have a redundant > pte_mkhuge() there. I guess it just got missed out, but you are right, there seems to be a redundant pte_mkhuge() in remove_migration_pte(), I will send out a patch dropping it off. > > Also, could we get rid of the one in mm/debug_vm_pgtable.c ? After this patch, arch_make_huge_pte() should be used instead in generic MM for all cases. So you are suggesting arch_make_huge_pte() should be tested instead ? diff --git a/mm/debug_vm_pgtable.c b/mm/debug_vm_pgtable.c index c631ade3f1d2..15ee86034ddc 100644 --- a/mm/debug_vm_pgtable.c +++ b/mm/debug_vm_pgtable.c @@ -909,7 +909,7 @@ static void __init hugetlb_basic_tests(struct pgtable_debug_args *args) #ifdef CONFIG_ARCH_WANT_GENERAL_HUGETLB pte = pfn_pte(args->fixed_pmd_pfn, args->page_prot); - WARN_ON(!pte_huge(pte_mkhuge(pte))); + WARN_ON(!pte_huge(arch_make_huge_pte(pte))); #endif /* CONFIG_ARCH_WANT_GENERAL_HUGETLB */ } #else /* !CONFIG_HUGETLB_PAGE */ > > Also, shouldn't arch_make_huge_pte() be documented in > Documentation/vm/arch_pgtable_helpers.rst instead of pte_mkhuge() ? diff --git a/Documentation/mm/arch_pgtable_helpers.rst b/Documentation/mm/arch_pgtable_helpers.rst index fd2a19df884e..07a0618f84de 100644 --- a/Documentation/mm/arch_pgtable_helpers.rst +++ b/Documentation/mm/arch_pgtable_helpers.rst @@ -216,7 +216,7 @@ HugeTLB Page Table Helpers +---------------------------+--------------------------------------------------+ | pte_huge | Tests a HugeTLB | +---------------------------+--------------------------------------------------+ -| pte_mkhuge | Creates a HugeTLB | +| arch_make_huge_pte | Creates a HugeTLB | +---------------------------+--------------------------------------------------+ | huge_pte_dirty | Tests a dirty HugeTLB | +---------------------------+--------------------------------------------------+ I will send out a patch implementing the above changes. I guess pte_mkhuge() now will just be a platform helper, which can be folded into arch_make_huge_pte() if and when required. - Anshuman > > Christophe > >> >> 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 >> Reviewed-by: Christophe Leroy >> Acked-by: Mike Kravetz >> Signed-off-by: Anshuman Khandual >> --- >> This applies on v5.17-rc2 >> >> Changes in V2: >> >> - Direct PTE encode in arch_make_huge_pte() on powerpc platform per Christophe >> >> Changes in V1: >> >> https://lore.kernel.org/all/1643780286-18798-1-git-send-email-anshuman.khandual@arm.com/ >> >> arch/arm64/mm/hugetlbpage.c | 1 + >> arch/powerpc/include/asm/nohash/32/hugetlb-8xx.h | 4 ++-- >> arch/sparc/mm/hugetlbpage.c | 1 + >> include/linux/hugetlb.h | 2 +- >> mm/hugetlb.c | 3 +-- >> mm/vmalloc.c | 1 - >> 6 files changed, 6 insertions(+), 6 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..de092b04ee1a 100644 >> --- a/arch/powerpc/include/asm/nohash/32/hugetlb-8xx.h >> +++ b/arch/powerpc/include/asm/nohash/32/hugetlb-8xx.h >> @@ -71,9 +71,9 @@ static inline pte_t arch_make_huge_pte(pte_t entry, unsigned int shift, vm_flags >> size_t size = 1UL << shift; >> >> if (size == SZ_16K) >> - return __pte(pte_val(entry) & ~_PAGE_HUGE); >> + return __pte(pte_val(entry) | _PAGE_SPS); >> else >> - return entry; >> + return __pte(pte_val(entry) | _PAGE_SPS | _PAGE_HUGE); >> } >> #define arch_make_huge_pte arch_make_huge_pte >> #endif >> diff --git a/arch/sparc/mm/hugetlbpage.c b/arch/sparc/mm/hugetlbpage.c >> index 0f49fada2093..d8e0e3c7038d 100644 >> --- a/arch/sparc/mm/hugetlbpage.c >> +++ b/arch/sparc/mm/hugetlbpage.c >> @@ -181,6 +181,7 @@ pte_t arch_make_huge_pte(pte_t entry, unsigned int shift, vm_flags_t flags) >> { >> pte_t pte; >> >> + entry = pte_mkhuge(entry); >> pte = hugepage_shift_to_tte(entry, shift); >> >> #ifdef CONFIG_SPARC64 >> diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h >> index d1897a69c540..52c462390aee 100644 >> --- a/include/linux/hugetlb.h >> +++ b/include/linux/hugetlb.h >> @@ -754,7 +754,7 @@ static inline void arch_clear_hugepage_flags(struct page *page) { } >> static inline pte_t arch_make_huge_pte(pte_t entry, unsigned int shift, >> vm_flags_t flags) >> { >> - return entry; >> + return pte_mkhuge(entry); >> } >> #endif >> >> diff --git a/mm/hugetlb.c b/mm/hugetlb.c >> index 61895cc01d09..5ca253c1b4e4 100644 >> --- a/mm/hugetlb.c >> +++ b/mm/hugetlb.c >> @@ -4637,7 +4637,6 @@ static pte_t make_huge_pte(struct vm_area_struct *vma, struct page *page, >> vma->vm_page_prot)); >> } >> entry = pte_mkyoung(entry); >> - entry = pte_mkhuge(entry); >> entry = arch_make_huge_pte(entry, shift, vma->vm_flags); >> >> return entry; >> @@ -6172,7 +6171,7 @@ unsigned long hugetlb_change_protection(struct vm_area_struct *vma, >> unsigned int shift = huge_page_shift(hstate_vma(vma)); >> >> old_pte = huge_ptep_modify_prot_start(vma, address, ptep); >> - pte = pte_mkhuge(huge_pte_modify(old_pte, newprot)); >> + pte = huge_pte_modify(old_pte, newprot); >> pte = arch_make_huge_pte(pte, shift, vma->vm_flags); >> huge_ptep_modify_prot_commit(vma, address, ptep, old_pte, pte); >> pages++; >> diff --git a/mm/vmalloc.c b/mm/vmalloc.c >> index 4165304d3547..d0b14dd73adc 100644 >> --- a/mm/vmalloc.c >> +++ b/mm/vmalloc.c >> @@ -118,7 +118,6 @@ static int vmap_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end, >> if (size != PAGE_SIZE) { >> pte_t entry = pfn_pte(pfn, prot); >> >> - entry = pte_mkhuge(entry); >> entry = arch_make_huge_pte(entry, ilog2(size), 0); >> set_huge_pte_at(&init_mm, addr, pte, entry); >> pfn += PFN_DOWN(size);