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 77F662AEED for ; Mon, 28 Apr 2025 12:04:38 +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=1745841880; cv=none; b=RSIWgiKS2wEaN8mqsjdQdGMCYKpAV8BuXmutYm/kM3DOkEx5IB1KfDYfGee11g8fcq3az+g/v07u/CxhbaytUGxDaP/Fu8yg3hUYAk1b7ExtITzUWrSPIr74dsGZ0P4QlsBjrz9X6yVk4JdGlp+NI1YoFf6Sk4toHNLhzRgg3c4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1745841880; c=relaxed/simple; bh=vBmy2/OFBQmtoZCZANDKIT5yIL4J+Nkr/N4mHP+NFms=; h=From:To:Cc:Subject:Date:Message-Id:MIME-Version; b=RJwJ7UDhnKvassNH5Oms28CJyM3H1u8UZAtBgpXLMub8k/ZgzQoiYk8egCOXIFgW0eRDXenTTuNiNJfzVB9suRZNFXGy3PjZCth2gbHQoTup2gqbMDIYInym+8K8n1yLhhnRHe7HozZ+HAe2vhHC+iWpZQut90qfVHGBXZonKLw= 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 107931516; Mon, 28 Apr 2025 05:04:31 -0700 (PDT) Received: from K4MQJ0H1H2.arm.com (unknown [10.163.78.210]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id E54B93F66E; Mon, 28 Apr 2025 05:04:27 -0700 (PDT) From: Dev Jain To: 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, Dev Jain Subject: [PATCH 0/7] Optimize mprotect for large folios Date: Mon, 28 Apr 2025 17:34:07 +0530 Message-Id: <20250428120414.12101-1-dev.jain@arm.com> X-Mailer: git-send-email 2.39.3 (Apple Git-146) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 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(-) -- 2.30.2