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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 95617C369DC for ; Mon, 28 Apr 2025 12:30:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: MIME-Version:Message-Id:Date:Subject:Cc:To:From:Reply-To:Content-Type: Content-ID:Content-Description:Resent-Date:Resent-From:Resent-Sender: Resent-To:Resent-Cc:Resent-Message-ID:In-Reply-To:References:List-Owner; bh=q0ek+w7Cj3PNAbRgahJDh4ULM0v6Ru1SXEA0WTuCJDg=; b=XEvZEDwubXcV4YXdAB7ayipVRq t4iCXSfz7DLdu75zqqOiRgeFKMlJ1JGL9D3h7G3lzb0mUFvDthSJBRF5heX0UtRxeyHO1k6rTKmJV XRYbGog5Yrc6fDOG4H7SugKWSrQnmvD1nwvHRJXi+3fW81qXbjVw9HPie3+75aBdebMMKbTsXcOWx 9wTb2WISON+XJq8fPEwn4qUkNsoBdb3z/unZjGqH1s1W5Tx4XoZsyR17Nvf0NhGSUf/GvgverqOi/ IopB8GQ0YaynIR0r6bqBJ4yaGH/n048DUUdJMG8GQSwzJJjJ3HU0rlgWfv34YYAHjEgreYxL35A3m 7vJLCkzA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1u9NcP-00000006Bsn-0WhA; Mon, 28 Apr 2025 12:29:53 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1u9NDy-000000065fr-1R92 for linux-arm-kernel@lists.infradead.org; Mon, 28 Apr 2025 12:04:39 +0000 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) MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20250428_050438_426180_6F5C115C X-CRM114-Status: UNSURE ( 7.46 ) X-CRM114-Notice: Please train this message. X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org 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