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 970401EEE0 for ; Tue, 29 Apr 2025 04:40:38 +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=1745901640; cv=none; b=qKhE6tkuKGl08/jg6urRzwrWNo0aPc/BshzSSYvrjmu0/C5AbFNUuN/3weLDXLfBP4GrNpDtZWPt3HNVMb4cGlNqoGWnnYMpIbawaPOnuTW2WBUJLzfFRgGGzYa6pT+CDu4oBdXgBmmChtnQ+kIIONt8MnfvTTO0Gcm52iN5wgg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1745901640; c=relaxed/simple; bh=tqo3K8EOZCZ80SSV7GclaBkSWb/nj7Zj5u+SzSelJGo=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=otR/+dcFYs+U8trmcyBv5/7LlJwulqLbHNI0Wf9SHUaJYEO/w8nb/AJ+3p+/gwlyUwoqD0rmKASlo+czUoWJels7TVYGVx77OFbMiXQWLg9LtXcbFYVnv+Lc5oqnoWLhXckpiWtFt6sDDVTuqSv9Efs4DF/JU98XWlT2bQXCuRo= 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 F32A01515; Mon, 28 Apr 2025 21:40:30 -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 460203F66E; Mon, 28 Apr 2025 21:40:27 -0700 (PDT) Message-ID: <1bf29e9d-2e85-46ce-b8bf-d2ca5ec6bddd@arm.com> Date: Tue, 29 Apr 2025 10:10:24 +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 0/7] Optimize mprotect for large folios To: Lance Yang , akpm@linux-foundation.org Cc: 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, ziy@nvidia.com References: <20250428120414.12101-1-dev.jain@arm.com> <2c70d515-f02e-477a-afc5-d3a25f6c9c0d@linux.dev> Content-Language: en-US From: Dev Jain In-Reply-To: <2c70d515-f02e-477a-afc5-d3a25f6c9c0d@linux.dev> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit On 28/04/25 7:01 pm, Lance Yang wrote: > I'm hitting the following compilation errors after applying this patch > series: Not sure why is that. I cherry-picked my commits onto 6ebffe676fcf8d259e3fb5d5fbf1a8227f22182c and the kernel builds for me. Let me send a v2 rebased onto this. > > In file included from ./include/linux/kasan.h:37, >                  from ./include/linux/slab.h:260, >                  from ./include/linux/crypto.h:19, >                  from arch/x86/kernel/asm-offsets.c:9: > ./include/linux/pgtable.h: In function ‘modify_prot_start_ptes’: > ./include/linux/pgtable.h:905:15: error: implicit declaration of > function ‘ptep_modify_prot_start’ [-Werror=implicit-function-declaration] >   905 |         pte = ptep_modify_prot_start(vma, addr, ptep); >       |               ^~~~~~~~~~~~~~~~~~~~~~ > ./include/linux/pgtable.h:905:15: error: incompatible types when > assigning to type ‘pte_t’ from type ‘int’ > ./include/linux/pgtable.h:909:27: error: incompatible types when > assigning to type ‘pte_t’ from type ‘int’ >   909 |                 tmp_pte = ptep_modify_prot_start(vma, addr, ptep); >       |                           ^~~~~~~~~~~~~~~~~~~~~~ > ./include/linux/pgtable.h: In function ‘modify_prot_commit_ptes’: > ./include/linux/pgtable.h:925:17: error: implicit declaration of > function ‘ptep_modify_prot_commit’ [-Werror=implicit-function-declaration] >   925 |                 ptep_modify_prot_commit(vma, addr, ptep, > old_pte, pte); >       |                 ^~~~~~~~~~~~~~~~~~~~~~~ > ./include/linux/pgtable.h: At top level: > ./include/linux/pgtable.h:1360:21: error: conflicting types for > ‘ptep_modify_prot_start’; have ‘pte_t(struct vm_area_struct *, long > unsigned int,  pte_t *)’ >  1360 | static inline pte_t ptep_modify_prot_start(struct > vm_area_struct *vma, >       |                     ^~~~~~~~~~~~~~~~~~~~~~ > ./include/linux/pgtable.h:905:15: note: previous implicit declaration of > ‘ptep_modify_prot_start’ with type ‘int()’ >   905 |         pte = ptep_modify_prot_start(vma, addr, ptep); >       |               ^~~~~~~~~~~~~~~~~~~~~~ > ./include/linux/pgtable.h:1371:20: warning: conflicting types for > ‘ptep_modify_prot_commit’; have ‘void(struct vm_area_struct *, long > unsigned int,  pte_t *, pte_t,  pte_t)’ >  1371 | static inline void ptep_modify_prot_commit(struct > vm_area_struct *vma, >       |                    ^~~~~~~~~~~~~~~~~~~~~~~ > ./include/linux/pgtable.h:1371:20: error: static declaration of > ‘ptep_modify_prot_commit’ follows non-static declaration > ./include/linux/pgtable.h:925:17: note: previous implicit declaration of > ‘ptep_modify_prot_commit’ with type ‘void(struct vm_area_struct *, long > unsigned int,  pte_t *, pte_t,  pte_t)’ >   925 |                 ptep_modify_prot_commit(vma, addr, ptep, > old_pte, pte); >       |                 ^~~~~~~~~~~~~~~~~~~~~~~ > cc1: some warnings being treated as errors > make[2]: *** [scripts/Makefile.build:98: arch/x86/kernel/asm-offsets.s] > Error 1 > make[1]: *** [/home/runner/work/mm-test-robot/mm-test-robot/linux/ > Makefile:1280: prepare0] Error 2 > make: *** [Makefile:248: __sub-make] Error 2 > > Based on: > > mm-unstable b18dec6a6ad3d051dadc3c16fb838e4abddf8d3c ("mm/numa: remove > unnecessary local variable in alloc_node_data()") > > > Thanks, > Lance > > > > On 2025/4/28 20:04, Dev Jain wrote: >> This patchset optimizes the mprotect() system call for large folios >> by PTE-batching. >> >> We use the following test cases to measure performance, mprotect()'ing >> the mapped memory to read-only then read-write 40 times: >> >> Test case 1: Mapping 1G of memory, touching it to get PMD-THPs, then >> pte-mapping those THPs >> Test case 2: Mapping 1G of memory with 64K mTHPs >> Test case 3: Mapping 1G of memory with 4K pages >> >> Average execution time on arm64, Apple M3: >> Before the patchset: >> T1: 7.9 seconds   T2: 7.9 seconds   T3: 4.2 seconds >> >> After the patchset: >> T1: 2.1 seconds   T2: 2.2 seconds   T3: 4.2 seconds >> >> Observing T1/T2 and T3 before the patchset, we also remove the regression >> introduced by ptep_get() on a contpte block. And, for large folios we get >> an almost 276% performance improvement. >> >> Dev Jain (7): >>    mm: Refactor code in mprotect >>    mm: Optimize mprotect() by batch-skipping PTEs >>    mm: Add batched versions of ptep_modify_prot_start/commit >>    arm64: Add batched version of ptep_modify_prot_start >>    arm64: Add batched version of ptep_modify_prot_commit >>    mm: Batch around can_change_pte_writable() >>    mm: Optimize mprotect() through PTE-batching >> >>   arch/arm64/include/asm/pgtable.h |  10 ++ >>   arch/arm64/mm/mmu.c              |  21 +++- >>   include/linux/mm.h               |   4 +- >>   include/linux/pgtable.h          |  42 ++++++++ >>   mm/gup.c                         |   2 +- >>   mm/huge_memory.c                 |   4 +- >>   mm/memory.c                      |   6 +- >>   mm/mprotect.c                    | 163 +++++++++++++++++++++---------- >>   mm/pgtable-generic.c             |  16 ++- >>   9 files changed, 198 insertions(+), 70 deletions(-) >> > >