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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 80C60C369CB for ; Tue, 29 Apr 2025 07:06:52 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 191EA6B0008; Tue, 29 Apr 2025 03:06:51 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 141AA6B000A; Tue, 29 Apr 2025 03:06:51 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 02D5F6B0012; Tue, 29 Apr 2025 03:06:50 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0014.hostedemail.com [216.40.44.14]) by kanga.kvack.org (Postfix) with ESMTP id DA9526B0008 for ; Tue, 29 Apr 2025 03:06:50 -0400 (EDT) Received: from smtpin17.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay10.hostedemail.com (Postfix) with ESMTP id 709B8C1161 for ; Tue, 29 Apr 2025 07:06:51 +0000 (UTC) X-FDA: 83386199022.17.6D2CD2E Received: from out-185.mta0.migadu.com (out-185.mta0.migadu.com [91.218.175.185]) by imf11.hostedemail.com (Postfix) with ESMTP id 7FE6140002 for ; Tue, 29 Apr 2025 07:06:49 +0000 (UTC) Authentication-Results: imf11.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=fVDMhRWN; dmarc=pass (policy=none) header.from=linux.dev; spf=pass (imf11.hostedemail.com: domain of lance.yang@linux.dev designates 91.218.175.185 as permitted sender) smtp.mailfrom=lance.yang@linux.dev ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1745910409; a=rsa-sha256; cv=none; b=GrFtibTbVy2xYA40ijiV9ymIMGA5F7TpB9tbgdnTWEDAKMbJCxflGd8Ie6AWEirvut8yPx 1a4fPki/UN+htCLTIDPQtilbNsKtZNzQMPtj2p4M8tDU745lwRYxLSf9ngUddVq/cruTV1 9GZbGAdKZSzjB2os0COtH06WH0Z1VD4= ARC-Authentication-Results: i=1; imf11.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=fVDMhRWN; dmarc=pass (policy=none) header.from=linux.dev; spf=pass (imf11.hostedemail.com: domain of lance.yang@linux.dev designates 91.218.175.185 as permitted sender) smtp.mailfrom=lance.yang@linux.dev ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1745910409; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=M1HJrQJGWIT9AFf/jcCjNDbRZ0ry2drXdhiftJCR3bw=; b=23XT0WUTM6oVG4qlUCHGBw+qBQq4+XZh/8dl6MPtrsa5ZD967dNfYqxokGujadi1/EVP1D UsmGavKjjNghxOeXUyVeXuWxWPKqLbzwtbPt49rvqSB09PTSAIZkd+uSyVcqSqcX/Gpc0D p/ZPd44BXAPCsEUxRgG7JqAjC+Ho3Dc= Message-ID: DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1745910407; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=M1HJrQJGWIT9AFf/jcCjNDbRZ0ry2drXdhiftJCR3bw=; b=fVDMhRWNp7xitc5a/aioHm5KvwDVTcs6s0xsh7qTE0whrr/+wD0frft+l6OumMnKYiexUe rTXh6TDb3pL9NMCXnx05kZQq0liV5JyWH8SSE2u22wjLZbbODECgHiSQx3AjUYs0hE48jo aizdjveLyaM61eZSFJEEeDl0jtKZkgk= Date: Tue, 29 Apr 2025 15:06:33 +0800 MIME-Version: 1.0 Subject: Re: [PATCH v2 0/7] Optimize mprotect for large folios To: Dev Jain , 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: <20250429052336.18912-1-dev.jain@arm.com> Content-Language: en-US X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Lance Yang In-Reply-To: <20250429052336.18912-1-dev.jain@arm.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-Migadu-Flow: FLOW_OUT X-Rspamd-Queue-Id: 7FE6140002 X-Stat-Signature: zu1ddqtrap4q3tnngn3eoiq6a9jnsdx6 X-Rspam-User: X-Rspamd-Server: rspam08 X-HE-Tag: 1745910409-309467 X-HE-Meta: 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 2E5sHNCm d1Wi9pYuib8qsYXlEc2hMZJEk0cYvFejBqAPtk3L/B/uWCYdEbdOWs2JSZNCIQx7gAlrvcl8cKmytDjeRWbTHQLc/8R6Cz2U+tkxjy9pk2/5gkdt3Y3NwTL2rBWQ7caSVgG82l9yvxOYowbfKxVg9tCww0gkPsLC8toz8HtRupEYlFWJN2OpLffF82KQhyk8gs2/6WpO77s0Mr4P0uc5b+ZXGFg== X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: Hey Dev, Hmm... I also hit the same compilation errors: 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); | ^~~~~~~~~~~~~~~~~~~~~~~ CC /home/runner/work/mm-test-robot/mm-test-robot/linux/tools/objtool/libstring.o CC /home/runner/work/mm-test-robot/mm-test-robot/linux/tools/objtool/libctype.o CC /home/runner/work/mm-test-robot/mm-test-robot/linux/tools/objtool/str_error_r.o CC /home/runner/work/mm-test-robot/mm-test-robot/linux/tools/objtool/librbtree.o 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[1]: *** Waiting for unfinished jobs.... LD /home/runner/work/mm-test-robot/mm-test-robot/linux/tools/objtool/objtool-in.o LINK /home/runner/work/mm-test-robot/mm-test-robot/linux/tools/objtool/objtool make: *** [Makefile:248: __sub-make] Error 2 Well, modify_prot_start_ptes() calls ptep_modify_prot_start(), but x86 does not define __HAVE_ARCH_PTEP_MODIFY_PROT_TRANSACTION. To avoid implicit declaration errors, the architecture-independent ptep_modify_prot_start() must be defined before modify_prot_start_ptes(). With the changes below, things work correctly now ;) diff --git a/include/linux/pgtable.h b/include/linux/pgtable.h index 10cdb87ccecf..d9d6c49bb914 100644 --- a/include/linux/pgtable.h +++ b/include/linux/pgtable.h @@ -895,44 +895,6 @@ static inline void wrprotect_ptes(struct mm_struct *mm, unsigned long addr, } #endif -/* See the comment for ptep_modify_prot_start */ -#ifndef modify_prot_start_ptes -static inline pte_t modify_prot_start_ptes(struct vm_area_struct *vma, - unsigned long addr, pte_t *ptep, unsigned int nr) -{ - pte_t pte, tmp_pte; - - pte = ptep_modify_prot_start(vma, addr, ptep); - while (--nr) { - ptep++; - addr += PAGE_SIZE; - tmp_pte = ptep_modify_prot_start(vma, addr, ptep); - if (pte_dirty(tmp_pte)) - pte = pte_mkdirty(pte); - if (pte_young(tmp_pte)) - pte = pte_mkyoung(pte); - } - return pte; -} -#endif - -/* See the comment for ptep_modify_prot_commit */ -#ifndef modify_prot_commit_ptes -static inline void modify_prot_commit_ptes(struct vm_area_struct *vma, unsigned long addr, - pte_t *ptep, pte_t old_pte, pte_t pte, unsigned int nr) -{ - for (;;) { - ptep_modify_prot_commit(vma, addr, ptep, old_pte, pte); - if (--nr == 0) - break; - ptep++; - addr += PAGE_SIZE; - old_pte = pte_next_pfn(old_pte); - pte = pte_next_pfn(pte); - } -} -#endif - /* * On some architectures hardware does not set page access bit when accessing * memory page, it is responsibility of software setting this bit. It brings @@ -1375,6 +1337,45 @@ static inline void ptep_modify_prot_commit(struct vm_area_struct *vma, __ptep_modify_prot_commit(vma, addr, ptep, pte); } #endif /* __HAVE_ARCH_PTEP_MODIFY_PROT_TRANSACTION */ + +/* See the comment for ptep_modify_prot_start */ +#ifndef modify_prot_start_ptes +static inline pte_t modify_prot_start_ptes(struct vm_area_struct *vma, + unsigned long addr, pte_t *ptep, unsigned int nr) +{ + pte_t pte, tmp_pte; + + pte = ptep_modify_prot_start(vma, addr, ptep); + while (--nr) { + ptep++; + addr += PAGE_SIZE; + tmp_pte = ptep_modify_prot_start(vma, addr, ptep); + if (pte_dirty(tmp_pte)) + pte = pte_mkdirty(pte); + if (pte_young(tmp_pte)) + pte = pte_mkyoung(pte); + } + return pte; +} +#endif + +/* See the comment for ptep_modify_prot_commit */ +#ifndef modify_prot_commit_ptes +static inline void modify_prot_commit_ptes(struct vm_area_struct *vma, unsigned long addr, + pte_t *ptep, pte_t old_pte, pte_t pte, unsigned int nr) +{ + for (;;) { + ptep_modify_prot_commit(vma, addr, ptep, old_pte, pte); + if (--nr == 0) + break; + ptep++; + addr += PAGE_SIZE; + old_pte = pte_next_pfn(old_pte); + pte = pte_next_pfn(pte); + } +} +#endif + #endif /* CONFIG_MMU */ /* -- Thanks, Lance On 2025/4/29 13:23, 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 74% performance improvement. > > v1->v2: > - Rebase onto mm-unstable (6ebffe676fcf: util_macros.h: make the header more resilient) > - Abridge the anon-exclusive condition (Lance Yang) > > 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 | 165 ++++++++++++++++++++----------- > mm/pgtable-generic.c | 16 ++- > 9 files changed, 198 insertions(+), 72 deletions(-) >