From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 81C8A155A4E for ; Tue, 29 Apr 2025 04:44:26 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.140.110.172 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1745901868; cv=none; b=DwCMbCCmliLgFDVy1gSFCJ764YdKW2FFnxvJ4IJvBboG4lGhejjjD4+jEABMRra0mWUdVopnlV06qz+GOOGy79GGRgSF++WkrGpMkwjE9PEcohVnRMdkTPgHW2CKDHElls0pn4Rhgg7RUo1/U97vptL5gPgX111rIL3uIt4jshQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1745901868; c=relaxed/simple; bh=f5OrOIjEE4l52lao9X07OmlXr2IMJUsUqSLGXLh0JXc=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=I6gHhvdc2J8F7TgAaYccHUu/yK77mKUtLLBjfBj0St3u8KItymnsh4JMdrHEr6TyqRiFfQvaRjFJnBb68PjIxviZpdIWPIEAA/LUCuq0SYQBHKc13UzrK3+88myKIUtHXU2Dtr5n8nrcHAm7htjiz++cuA3oCjvjuUnzKypbUKM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com; spf=pass smtp.mailfrom=arm.com; arc=none smtp.client-ip=217.140.110.172 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=arm.com 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 074C81515; Mon, 28 Apr 2025 21:44:19 -0700 (PDT) Received: from [10.163.78.253] (unknown [10.163.78.253]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 76B3C3F66E; Mon, 28 Apr 2025 21:44:16 -0700 (PDT) Message-ID: <80ac39fc-3023-4a6c-87ff-05135a4e9abf@arm.com> Date: Tue, 29 Apr 2025 10:14:12 +0530 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 4/7] arm64: Add batched version of ptep_modify_prot_start To: Zi Yan Cc: akpm@linux-foundation.org, ryan.roberts@arm.com, david@redhat.com, willy@infradead.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, catalin.marinas@arm.com, will@kernel.org, Liam.Howlett@oracle.com, lorenzo.stoakes@oracle.com, vbabka@suse.cz, jannh@google.com, anshuman.khandual@arm.com, peterx@redhat.com, joey.gouly@arm.com, ioworker0@gmail.com, baohua@kernel.org, kevin.brodsky@arm.com, quic_zhenhuah@quicinc.com, christophe.leroy@csgroup.eu, yangyicong@hisilicon.com, linux-arm-kernel@lists.infradead.org, namit@vmware.com, hughd@google.com, yang@os.amperecomputing.com References: <20250428120414.12101-1-dev.jain@arm.com> <20250428120414.12101-5-dev.jain@arm.com> <3D9FEC39-98C8-435B-BEA0-BD30EBB05E79@nvidia.com> Content-Language: en-US From: Dev Jain In-Reply-To: <3D9FEC39-98C8-435B-BEA0-BD30EBB05E79@nvidia.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit On 28/04/25 11:36 pm, Zi Yan wrote: > On 28 Apr 2025, at 8:04, Dev Jain wrote: > >> Override the generic definition to use get_and_clear_full_ptes(), so that >> we do a TLBI possibly only on the "contpte-edges" of the large PTE block, > > What do you mean by “contpte-edges”? Can you provide an example? get_and_clear_full_ptes -> contpte_get_and_clear_full_ptes -> contpte_try_unfold_partial, which unfolds only the start and end contpte block. Whereas, ptep_get_and_clear -> contpte_try_unfold, which means it will unfold for every contpte block. > >> instead of doing it for every contpte block, which happens for ptep_get_and_clear(). >> >> Signed-off-by: Dev Jain >> --- >> arch/arm64/include/asm/pgtable.h | 5 +++++ >> arch/arm64/mm/mmu.c | 12 +++++++++--- >> include/linux/pgtable.h | 4 ++++ >> mm/pgtable-generic.c | 16 +++++++++++----- >> 4 files changed, 29 insertions(+), 8 deletions(-) >> >> diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h >> index 2a77f11b78d5..8872ea5f0642 100644 >> --- a/arch/arm64/include/asm/pgtable.h >> +++ b/arch/arm64/include/asm/pgtable.h >> @@ -1553,6 +1553,11 @@ extern void ptep_modify_prot_commit(struct vm_area_struct *vma, >> unsigned long addr, pte_t *ptep, >> pte_t old_pte, pte_t new_pte); >> >> +#define modify_prot_start_ptes modify_prot_start_ptes >> +extern pte_t modify_prot_start_ptes(struct vm_area_struct *vma, >> + unsigned long addr, pte_t *ptep, >> + unsigned int nr); >> + >> #ifdef CONFIG_ARM64_CONTPTE >> >> /* >> diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c >> index 8fcf59ba39db..fe60be8774f4 100644 >> --- a/arch/arm64/mm/mmu.c >> +++ b/arch/arm64/mm/mmu.c >> @@ -1523,7 +1523,8 @@ static int __init prevent_bootmem_remove_init(void) >> early_initcall(prevent_bootmem_remove_init); >> #endif >> >> -pte_t ptep_modify_prot_start(struct vm_area_struct *vma, unsigned long addr, pte_t *ptep) >> +pte_t modify_prot_start_ptes(struct vm_area_struct *vma, unsigned long addr, >> + pte_t *ptep, unsigned int nr) > > Putting ptes at the end seems to break the naming convention. How about > ptep_modify_prot_range_start? ptes_modify_prot_start might be OK too. I was actually following the convention present in include/linux/pgtable.h, look at all the functions with _ptes suffix. > >> { >> if (alternative_has_cap_unlikely(ARM64_WORKAROUND_2645198)) { >> /* >> @@ -1532,9 +1533,14 @@ pte_t ptep_modify_prot_start(struct vm_area_struct *vma, unsigned long addr, pte >> * in cases where cpu is affected with errata #2645198. >> */ >> if (pte_user_exec(ptep_get(ptep))) >> - return ptep_clear_flush(vma, addr, ptep); >> + return clear_flush_ptes(vma, addr, ptep, nr); >> } >> - return ptep_get_and_clear(vma->vm_mm, addr, ptep); >> + return get_and_clear_full_ptes(vma->vm_mm, addr, ptep, nr, 0); >> +} >> + >> +pte_t ptep_modify_prot_start(struct vm_area_struct *vma, unsigned long addr, pte_t *ptep) >> +{ >> + return modify_prot_start_ptes(vma, addr, ptep, 1); >> } >> >> void ptep_modify_prot_commit(struct vm_area_struct *vma, unsigned long addr, pte_t *ptep, >> diff --git a/include/linux/pgtable.h b/include/linux/pgtable.h >> index ed287289335f..10cdb87ccecf 100644 >> --- a/include/linux/pgtable.h >> +++ b/include/linux/pgtable.h >> @@ -828,6 +828,10 @@ extern pte_t ptep_clear_flush(struct vm_area_struct *vma, >> pte_t *ptep); >> #endif >> >> +extern pte_t clear_flush_ptes(struct vm_area_struct *vma, >> + unsigned long address, >> + pte_t *ptep, unsigned int nr); >> + >> #ifndef __HAVE_ARCH_PMDP_HUGE_CLEAR_FLUSH >> extern pmd_t pmdp_huge_clear_flush(struct vm_area_struct *vma, >> unsigned long address, >> diff --git a/mm/pgtable-generic.c b/mm/pgtable-generic.c >> index 5a882f2b10f9..e238f88c3cac 100644 >> --- a/mm/pgtable-generic.c >> +++ b/mm/pgtable-generic.c >> @@ -90,17 +90,23 @@ int ptep_clear_flush_young(struct vm_area_struct *vma, >> } >> #endif >> >> -#ifndef __HAVE_ARCH_PTEP_CLEAR_FLUSH >> -pte_t ptep_clear_flush(struct vm_area_struct *vma, unsigned long address, >> - pte_t *ptep) >> +pte_t clear_flush_ptes(struct vm_area_struct *vma, unsigned long address, >> + pte_t *ptep, unsigned int nr) >> { > > Ditto. > >> struct mm_struct *mm = (vma)->vm_mm; >> pte_t pte; >> - pte = ptep_get_and_clear(mm, address, ptep); >> + pte = get_and_clear_full_ptes(mm, address, ptep, nr, 0); >> if (pte_accessible(mm, pte)) >> - flush_tlb_page(vma, address); >> + flush_tlb_range(vma, address, address + nr * PAGE_SIZE); >> return pte; >> } >> + >> +#ifndef __HAVE_ARCH_PTEP_CLEAR_FLUSH >> +pte_t ptep_clear_flush(struct vm_area_struct *vma, unsigned long address, >> + pte_t *ptep) >> +{ >> + return clear_flush_ptes(vma, address, ptep, 1); >> +} >> #endif >> >> #ifdef CONFIG_TRANSPARENT_HUGEPAGE >> -- >> 2.30.2 > > > Best Regards, > Yan, Zi