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]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id E5B00CA1009 for ; Wed, 3 Sep 2025 09:19:14 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 4C9698E000C; Wed, 3 Sep 2025 05:19:14 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 4A3A48E0001; Wed, 3 Sep 2025 05:19:14 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 3684C8E000C; Wed, 3 Sep 2025 05:19:14 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0015.hostedemail.com [216.40.44.15]) by kanga.kvack.org (Postfix) with ESMTP id 21A678E0001 for ; Wed, 3 Sep 2025 05:19:14 -0400 (EDT) Received: from smtpin06.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay06.hostedemail.com (Postfix) with ESMTP id BD8B511A203 for ; Wed, 3 Sep 2025 09:19:13 +0000 (UTC) X-FDA: 83847390186.06.F50C45D Received: from MRWPR03CU001.outbound.protection.outlook.com (mail-francesouthazon11011011.outbound.protection.outlook.com [40.107.130.11]) by imf03.hostedemail.com (Postfix) with ESMTP id 1B76420005 for ; Wed, 3 Sep 2025 09:19:09 +0000 (UTC) Authentication-Results: imf03.hostedemail.com; dkim=pass header.d=arm.com header.s=selector1 header.b=jD0nXIYH; dkim=pass header.d=arm.com header.s=selector1 header.b=jD0nXIYH; spf=pass (imf03.hostedemail.com: domain of Dev.Jain@arm.com designates 40.107.130.11 as permitted sender) smtp.mailfrom=Dev.Jain@arm.com; dmarc=pass (policy=none) header.from=arm.com; arc=pass ("microsoft.com:s=arcselector10001:i=2") ARC-Message-Signature: i=3; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1756891150; 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=eKdToSC7NupNaxSDJpkyXrCPGInIYIJL+4FM+pkALuM=; b=oYEYTmrXtxenUpeh702TSHOJJd3p6oSWuY5fYrkI0TYUSIWwt3HucolVsIgnbhodYrf/eC WK/10mYEzwsheO9GTfogZA3fUmoGl03iPJQtSCiOFWLc0Yiiy6FIAPKINdyFIICByUyOZJ fKKvs+r3nNrJB1dccEnVvUlrS7CyOFU= ARC-Authentication-Results: i=3; imf03.hostedemail.com; dkim=pass header.d=arm.com header.s=selector1 header.b=jD0nXIYH; dkim=pass header.d=arm.com header.s=selector1 header.b=jD0nXIYH; spf=pass (imf03.hostedemail.com: domain of Dev.Jain@arm.com designates 40.107.130.11 as permitted sender) smtp.mailfrom=Dev.Jain@arm.com; dmarc=pass (policy=none) header.from=arm.com; arc=pass ("microsoft.com:s=arcselector10001:i=2") ARC-Seal: i=3; s=arc-20220608; d=hostedemail.com; t=1756891150; a=rsa-sha256; cv=pass; b=K1WDbxPhvhsDECNPpygiTz3BpsjitRD03FMIDJlh1WcYwWA/9/0j7hmBiPzbGJLhfFBXxn LAVw3kG0vcBJGBVmlnc1W9la1fESW4fMuOIpYhKnAjj+2CvgQzO/NXxUuwvfUWZqHhmBBJ T4dxuXCsqJhGtKKygxbxQNfJY08T0Kw= ARC-Seal: i=2; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=pass; b=XglIcSKtGVIbZjCLt85LiQM81+Xdrk7BvV2v9W2zZh8NgpB67dZKGLNnqJ63AQ42u2N/pxoe4n06x6L6afIoNoK1kd2biav2orTg6MPVx3zAuLBiRbMdT/fZxqRWQQ+9JWoCZK5T5gkUiWYH7rEKzs6EH3nX+6GudsFWmN11pfBEqYOOsAGCeuz4Z8Kd6UFmLN4aPKD8AIrv2ixoGhTF9kcSGVWEg6Fh3WLvmGvUlVQ9Sud50tCCwguF0Yc6UNlFPHImIOnR064EB/lwMbr6KvtrNeG5nOGc+THBr9mq+duPybjgZLD3I5dmi6C8XYbnokUKOZGUj9YoPIo7zE/E5Q== ARC-Message-Signature: i=2; a=rsa-sha256; c=relaxed/relaxed; d=microsoft.com; s=arcselector10001; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-AntiSpam-MessageData-ChunkCount:X-MS-Exchange-AntiSpam-MessageData-0:X-MS-Exchange-AntiSpam-MessageData-1; bh=eKdToSC7NupNaxSDJpkyXrCPGInIYIJL+4FM+pkALuM=; b=Kw2A0U9uaXABhgUVYJbebabeZsatit0+GsYosvDKaS79C5kIcsWVDquuwodLevbUkuLktbfcqQEj8vWXPU0xal1F4u4etDUNLOIoJGjyrpSaMnhAKaUCbizeHLCkrcaamY5MR+s25qIwPKdwWdwIGW4/I4WtfhaLJjrurq2M+hkKJvmvaPvCb7Uyx/eYiEJ76uZqv5sSkz7aBukJwxouAIP19HyS3AwL0bWVKxKPbC1TpYa6mpbVeRtzQ41WEkuyhsaK4Cns770Zv/C0huQN/CibyWi/hX+WX2xT3pEXzqh3TRobcfsR0Oys/XDvESb9aQGccJr1fCDc4XtPszHcSQ== ARC-Authentication-Results: i=2; mx.microsoft.com 1; spf=pass (sender ip is 4.158.2.129) smtp.rcpttodomain=gmail.com smtp.mailfrom=arm.com; dmarc=pass (p=none sp=none pct=100) action=none header.from=arm.com; dkim=pass (signature was verified) header.d=arm.com; arc=pass (0 oda=1 ltdi=1 spf=[1,1,smtp.mailfrom=arm.com] dkim=[1,1,header.d=arm.com] dmarc=[1,1,header.from=arm.com]) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=arm.com; s=selector1; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=eKdToSC7NupNaxSDJpkyXrCPGInIYIJL+4FM+pkALuM=; b=jD0nXIYH9IfqnduwtEzNn3QWAxqZFsWDnSW4bDiUNbZHkqLmPZMk3rZndzhsbskixZprgqdDQ3ePb1sxRohJGjsBndGscyAjjay0dPkIJ0mkAxvw4O8DaTYd2jlYuZheDHYfwhBwmIzV9DrgfLIBXjJPRNDmG+LXOTL6yN8GDxA= Received: from DU2PR04CA0324.eurprd04.prod.outlook.com (2603:10a6:10:2b5::29) by PAVPR08MB9723.eurprd08.prod.outlook.com (2603:10a6:102:31e::13) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.9073.27; Wed, 3 Sep 2025 09:19:05 +0000 Received: from DB5PEPF00014B97.eurprd02.prod.outlook.com (2603:10a6:10:2b5:cafe::63) by DU2PR04CA0324.outlook.office365.com (2603:10a6:10:2b5::29) with Microsoft SMTP Server (version=TLS1_3, cipher=TLS_AES_256_GCM_SHA384) id 15.20.9094.17 via Frontend Transport; Wed, 3 Sep 2025 09:19:04 +0000 X-MS-Exchange-Authentication-Results: spf=pass (sender IP is 4.158.2.129) smtp.mailfrom=arm.com; dkim=pass (signature was verified) header.d=arm.com;dmarc=pass action=none header.from=arm.com; Received-SPF: Pass (protection.outlook.com: domain of arm.com designates 4.158.2.129 as permitted sender) receiver=protection.outlook.com; client-ip=4.158.2.129; helo=outbound-uk1.az.dlp.m.darktrace.com; pr=C Received: from outbound-uk1.az.dlp.m.darktrace.com (4.158.2.129) by DB5PEPF00014B97.mail.protection.outlook.com (10.167.8.235) with Microsoft SMTP Server (version=TLS1_3, cipher=TLS_AES_256_GCM_SHA384) id 15.20.9094.14 via Frontend Transport; Wed, 3 Sep 2025 09:19:05 +0000 ARC-Seal: i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none; b=BZypCn2qNfrf4EEdYdmRBSrCqw/3l8ltMbHjkEXSKCjpddTqobsjmHdqH7ZRjaFz8v0dvCxrnTOIsTzCQ3ywPSdt4k1IyHrQPfMkglXwF5MxRAHoDLWb2Xe2q4jZWldd8Vla/JPNJjU+GEJj4rcMk1MFesrzp5cAeigvugrdBbwZG603Lv8KAbYad8QwCX/vSBIcSA0goNzWQq3bVJv3rIvIRI3stP6irw4/g4ZzRSalDgnSS0txjy61jX4fpGvTRUiREEJ1ftraZEV69mr/3l5gBYQwz+HOuYY2QYNBr96RR/tWWQaMtRbDzwy/kP5bMS8L9KYYo7DLSuCWZ7qXeQ== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=microsoft.com; s=arcselector10001; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-AntiSpam-MessageData-ChunkCount:X-MS-Exchange-AntiSpam-MessageData-0:X-MS-Exchange-AntiSpam-MessageData-1; bh=eKdToSC7NupNaxSDJpkyXrCPGInIYIJL+4FM+pkALuM=; b=PnBJzBHl5sXPagyQQgIM/eWmyFbIpUky2gxsWSux0BoLZ5yyjKKm3pUYOC9+eNcAuykO2xhk1vkKjOaQkQkC35If93LlED2Rp6JbYDGkQgDtexBRbMXRA89Tsy++MGEMHr94HABqMYEb5HTmQbUkXJ6eVPzt+yBh/0Is/ZCguSWPG1RdWDj+BmqabssI8a2svvt6O+0IFBb3eywFNzdwWq/F6tkDdDFKb3QWh/E7aFdSHq8zFy9LzjEUm8gKZxROn0PTL0Cgn/ZPxDKt+usYW/ZU+sD+9VohjvYeVZMbIRd80IuOrqyOQ0M2XiP9a37JU2TsjZ4Fr7jytN+Y+Z7OjQ== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=arm.com; dmarc=pass action=none header.from=arm.com; dkim=pass header.d=arm.com; arc=none DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=arm.com; s=selector1; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=eKdToSC7NupNaxSDJpkyXrCPGInIYIJL+4FM+pkALuM=; b=jD0nXIYH9IfqnduwtEzNn3QWAxqZFsWDnSW4bDiUNbZHkqLmPZMk3rZndzhsbskixZprgqdDQ3ePb1sxRohJGjsBndGscyAjjay0dPkIJ0mkAxvw4O8DaTYd2jlYuZheDHYfwhBwmIzV9DrgfLIBXjJPRNDmG+LXOTL6yN8GDxA= Authentication-Results-Original: dkim=none (message not signed) header.d=none;dmarc=none action=none header.from=arm.com; Received: from AM9PR08MB7120.eurprd08.prod.outlook.com (2603:10a6:20b:3dc::22) by DU0PR08MB9874.eurprd08.prod.outlook.com (2603:10a6:10:422::13) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.9073.27; Wed, 3 Sep 2025 09:18:33 +0000 Received: from AM9PR08MB7120.eurprd08.prod.outlook.com ([fe80::2933:29aa:2693:d12e]) by AM9PR08MB7120.eurprd08.prod.outlook.com ([fe80::2933:29aa:2693:d12e%5]) with mapi id 15.20.9073.026; Wed, 3 Sep 2025 09:18:33 +0000 Message-ID: <3bd9ff5d-de8a-469f-a7b0-41c192b23993@arm.com> Date: Wed, 3 Sep 2025 14:48:27 +0530 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 1/2] mm: Enable khugepaged to operate on non-writable VMAs From: Dev Jain To: Wei Yang Cc: akpm@linux-foundation.org, david@redhat.com, kas@kernel.org, willy@infradead.org, hughd@google.com, ziy@nvidia.com, baolin.wang@linux.alibaba.com, lorenzo.stoakes@oracle.com, Liam.Howlett@oracle.com, npache@redhat.com, ryan.roberts@arm.com, baohua@kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org References: <20250903054635.19949-1-dev.jain@arm.com> <20250903080839.wuivg2u7smyuxo5e@master> <0a52cb54-5633-4374-baa5-199194dfc2e1@arm.com> Content-Language: en-US In-Reply-To: <0a52cb54-5633-4374-baa5-199194dfc2e1@arm.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-ClientProxiedBy: MA0PR01CA0086.INDPRD01.PROD.OUTLOOK.COM (2603:1096:a01:ae::11) To AM9PR08MB7120.eurprd08.prod.outlook.com (2603:10a6:20b:3dc::22) MIME-Version: 1.0 X-MS-TrafficTypeDiagnostic: AM9PR08MB7120:EE_|DU0PR08MB9874:EE_|DB5PEPF00014B97:EE_|PAVPR08MB9723:EE_ X-MS-Office365-Filtering-Correlation-Id: c15b0f0e-9cda-4af3-a170-08ddeacaedfc x-checkrecipientrouted: true NoDisclaimer: true X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam-Untrusted: BCL:0;ARA:13230040|366016|1800799024|376014|7416014; X-Microsoft-Antispam-Message-Info-Original: =?utf-8?B?Sm81ZTlpOThkbXZBb0J6Z1h5Mkl5WEF2QTZ4b2ZrRzg2VnY1bjN6TldSZXNa?= =?utf-8?B?MWZMR3AxTVArVDhSdWlCWTF1UitiNkZZOS8rYjhFcTFhM3JVSVAvZ3pzUy9y?= =?utf-8?B?RHJpT0svOVduMVNWZzVVaGI1T21lZDVXalJYTDVrS05ocTFOQWRtZXY0eXcv?= =?utf-8?B?d3BidzBOOFozV0liekp4TTFFc2lwb2xydEloM2lRcVJkMzdva3Bia0dWb1RS?= =?utf-8?B?dnZMZzJ2ZGh3Zzh2M1dGVk11clNnQVdraXZCVjErNk5qVXhxUUJqWFNncmsr?= =?utf-8?B?c1FiL1pPMDlTR0JsVURreUh1TUp6WnhJOFRROThwSXA1Ny8wMEQ1bmI3VEF5?= =?utf-8?B?c3BKOGRvOWdCNWF5OTdwWE1TcXBWRzFuVk9DL2RTSU8wK2wxRnNqVU10YmNv?= =?utf-8?B?TjZvemtGeGtFUnJPR3Y1b2piK1hSSC9IVnAyUkFXb2hiQkpQSmllQUlRcDVx?= =?utf-8?B?YUpGTUJQb1FSMGtRMW1VVnZNOVI0bG5wOERjWFkzU0ZVdWVycmkyR1VDU3Nt?= =?utf-8?B?K1oyWCsrdWFJb3RLWGZaSU5zZGtyQ2ZEMWppSjFSZ3BUMmQzTUZIMVd0L25F?= =?utf-8?B?Q3hyZFc0VE5JQW5HNUJMcCtENDBVd1NYUE1mbkUwWkhFWHNuSUZRUEFRNHc4?= =?utf-8?B?SWxyVkw0V0JBR2Y0NDVBTEh1MnRoc2JGRXpITnBsdmxxRmpJOWJWKzAxREY1?= =?utf-8?B?YzhPMmh2TlBXeHRWaWlrOGR4TVJ4OXFOWUlTUVhkb1J5K1dWZldHeTdRZC9V?= =?utf-8?B?WXQyWWI2cE9sVGRxOHQ0Yzl1bENWR3M0RTV1Mjl5OUtzeHcvVWw4QnIvU1BS?= =?utf-8?B?UEs3ZnF3YzJ0MHdYUmdBdjdpVTY4QmliK0dRUXNtNG9KTVYycXYrbW1zN3JQ?= =?utf-8?B?NWx5aFZGSGFEb1hmVEliOTI5OHJoNWx1ZVVlc0tEYzNxR0ZrMllsWXNQVExo?= =?utf-8?B?aTJVZ1NPQ2FEcmtBejhrZlFYZjZHVlhUbUc1ZTNiaHl5Ky9EOUNySE1tc3RG?= =?utf-8?B?MFdIZXAxRGhXakRpRUU3c0hSRDRXclFxUnpGR1FIZW1oRTZqSFdBM0pFQ2pa?= =?utf-8?B?K2FqTUxjMXhoK0xmWmJwY2hLK20xMnlJZTh0QjZtaVdRUmc1M0hOaW9BejVx?= =?utf-8?B?R3R4ZlpwR3BidXJyWWlLVU1wNFNrNUFFcXI5SFBUTjVLMHJyWGY3TmI1dnRT?= =?utf-8?B?dE9yWHV0M1lhWXkxNlo2VkR6VlJKbWFCd2dLTmFEbWc2NGhOVGJiTGxubjZv?= =?utf-8?B?aFFJelVMbEJCTUo0MkVleFNjL1dJbm5udElvT0NTbS95SzNKZC9vUXd6Um9F?= =?utf-8?B?VnJZNEtEbktqOVNBU2MrNHVnS05pT0FndWNZdGFadHl0NElzV1dHOSt6ZVJ4?= =?utf-8?B?Z1RoTG5QUldydHh6QnBBQnVhMTJwdWhFdFIxbW9xMUpwUG1TdEVkakJreERJ?= =?utf-8?B?eHFqYlJlUmtaVjJzK0JQR1hISm45S01RYXhVVEdLaFdrOG5HVmUrVjVXUEwv?= =?utf-8?B?UTYzaThmaXNHcTUwL0VsNnkvYVUrNU9VQjZOQmZlOFpremFyTlF1ZVVza3lY?= =?utf-8?B?YmFZalR6YUpTRlk4eUhlR1hFSlcvTWhwZlltelpGVWRQbTREcVZPSTlabzJM?= =?utf-8?B?eVl6ZnRkRUVSeVI1M2dNdnZhVHVwVDBKUHd6RkQzL2NyWDIxbkpzeWwxeC9V?= =?utf-8?B?VmpNZnBmbjVYNDBYVWYyQlZkdTRUN0xVTkRMVEhCQ0VHMGUrSjBnV09OMS9P?= =?utf-8?B?UTAzb2hiY3FHa3p4cmVyMlNSY2x2cU9YZmMyNXhKZ1YzUVY0M1gxNzZCVFNC?= =?utf-8?B?b0pqV29aUXA3Z2hsUGIwREhOU1FmdWJmSjQwc0ZWVUppMjhGTnRRaFdMTWtV?= =?utf-8?B?ejZSRkJRU3pqWkdaRG42WUh3SDlxaTdBK0kvRjlxY2xBZXc9PQ==?= X-Forefront-Antispam-Report-Untrusted: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:AM9PR08MB7120.eurprd08.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230040)(366016)(1800799024)(376014)(7416014);DIR:OUT;SFP:1101; X-MS-Exchange-Transport-CrossTenantHeadersStamped: DU0PR08MB9874 X-EOPAttributedMessage: 0 X-MS-Exchange-Transport-CrossTenantHeadersStripped: DB5PEPF00014B97.eurprd02.prod.outlook.com X-MS-PublicTrafficType: Email X-MS-Office365-Filtering-Correlation-Id-Prvs: 0c921cd9-b1dd-4581-e508-08ddeacada8f X-Microsoft-Antispam: BCL:0;ARA:13230040|35042699022|82310400026|36860700013|1800799024|14060799003|376014|7416014; X-Microsoft-Antispam-Message-Info: =?utf-8?B?TVU5SDRvd2RLZFY2MTgvMWZENkgxamlFQUxScEV0MWpnYXlKb05heEtiV2Mx?= =?utf-8?B?QzhDUWtMZGNHd3ZkaFdaWkFqQ005RDRDb1pkWW1kc0p4TUtCbXdNOVQvOEN2?= =?utf-8?B?cHFaUjZyQnZ3bitacFJLOXdNVWxHenRSUjJGZ05XMk1YKzVGTWNxVHJSRDdI?= =?utf-8?B?bFRkTTN4S3IrTUQ1TFJCTWRjV2IwbHdjVEM0R0Z4SG5KaVVTY3FVOXpFb3VL?= =?utf-8?B?WnBNcW5vT3l4c0RkZTJUZDVpcjNldm5uVmh2L3Q3a1RPSW1IS20wbjdPN0tu?= =?utf-8?B?L1VWRVFNYnZEU2JJYTV4bWQ2WVl4MWJtdXRyTXlMQVBMdit2Ry9MQ0hSWjB5?= =?utf-8?B?UGtZdEpBNXhUSXVwck1xTTR0dzR5V2JBWHhMd3JaaUppWEl0VHNQMHBUVGFo?= =?utf-8?B?SGUyUGhPVzNBbDFOcDcwb1pVaVIvNnhnL1hFZWVaVCtOSjQwU2tJamdXSDdN?= =?utf-8?B?U3pGOUJLaCtxKzMrakJqcTViQVI0NjU0VkNxaG44ZDYxSEMxTHQ0M3FZL0oz?= =?utf-8?B?VitKdnFFMWRRZ05OVHJmYlA3dEx5YXUzbW4raUlYT3ZKTys4R0Q1Q0gyWjJh?= =?utf-8?B?V2IvcmFGU004ZDRMQ3lsbjU2RWZ6bEkvYXRhY2F6djVQWTY0aDYySDBlN28w?= =?utf-8?B?V0UwRHNuUS9vQkhOMS9BOThmSjFPNEVjWDNJQnhJRmRETnhwQzZjdU9zOGc2?= =?utf-8?B?Y2dkVHBNclNJUWpuR3hjbmsxR0gzRHhKQjczeDlCU0twRnRCSDFNc255eFQr?= =?utf-8?B?SFJDU25neGlVOWlmZXhnZzlrK013bTA3Y0EvcGFUN3ZMWmdzTHpIMUkrV0cv?= =?utf-8?B?eXM1a3ZtYmJqRFpUZFVDYmwxV25KTTJRRnhIQ0owVW9YdVRZYWd3QmVlZ1l3?= =?utf-8?B?Yng1V09QbmsyM3pyL21iVlR4dHcyVmsxUkk2dEFNcGlIVG1JZ1VTZXBFYmtt?= =?utf-8?B?ampTdWg5MWtKbkc3K0dnd0xvUU90OVNoYlZFdjZOdGtJcWJXcW1vK2wwNkg4?= =?utf-8?B?VWpjVTF5bkVTMEk4VkdpOVR1Nk1aK3lkOUxwc3JvNkVvWDZ3ZWoxdWVSM0R0?= =?utf-8?B?K2hJWEZZNWFRZVFaTHo4QXl5S0trUWZVYldoaHNBVW9ybUZjcEkvQVdoY0JW?= =?utf-8?B?ZFhHQWFTcDJpdXBCS0FlNDNuOWI4VmpjYkZsUFE5NUVOOTc4ZlhNZFQvaDIw?= =?utf-8?B?alNxSWVySFAxTEY1TDFLU2tia3lEM1dvZ0JZY0M0RDUrVVJmQlJvaEZZaUsw?= =?utf-8?B?Z2lJZE1GUjc0STFQYWF3c0x6SzhjdlFpNFRWZmMyUFgrVVF5Vlk4d2NDM1Zr?= =?utf-8?B?U3VxWDlrUXN0d3MxZCtKNDcrNTVNY0xHWXhXZ1ZqcmVFTndGVUpNWDdEQ1lN?= =?utf-8?B?c0hydFZ5WG0xTXR0eXozYS80ajAzMG93ZTVrNys0RmQ2cmpGYUxUOGkrbXlB?= =?utf-8?B?bkZwTUtsQXhyUlMvWXk3NGUzaHI1ZXg4NGM0citOTG82K3hka3plN3hjRU12?= =?utf-8?B?QXM5NG9nOENYMWNYcFFGL1R6ZGR6Q281Tk40NnRaM0ViNy9QVWFiZU55VnVs?= =?utf-8?B?bWp4UGIxNEwwdG9KUlFQQmVRbHcrN0xYdS9oY2Jmc0hoaHpBQzVJbFBwd2FB?= =?utf-8?B?UTEyWHhrQ3NwajlhbTN1SmE0MWlZYktBY3ZIZUVwdDIrMllENWwwQUVpL1Iv?= =?utf-8?B?cjNvZEdQV1A4dDJIa3FCZFJ1ZzNZQzVxWXZsZUZJMGxLQ1FBemlDaVRRY0ZI?= =?utf-8?B?R01NelFsS3crUXFJeEFSNGhyaHRVK3MvTUFsRjdvWXVhTFRJWCt5cmdBUFhO?= =?utf-8?B?dlpNSzR5cEQvUTdLaFNBaXdPZnZGUWtLdHVUdFAzODREQng1VnR1UlhzMS9G?= =?utf-8?B?SFdRMHNjN2Jyb2M2RkxNaFAvUzFtT2ZWWGhXNEt1SDhxZlY0MDZua2J5VURF?= =?utf-8?B?LzgyR1RYMWdHRUkvOWRWRGJxVkpUYnlZditiaThYd2hxSGE5M2ZoYUpUSWtS?= =?utf-8?B?SE9HY0pIU3lKSHduMWV3cm1xWXJtdmltTGRkcVNGc0R4S0pORVppekpZZEVQ?= =?utf-8?Q?+tNdTf?= X-Forefront-Antispam-Report: CIP:4.158.2.129;CTRY:GB;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:outbound-uk1.az.dlp.m.darktrace.com;PTR:InfoDomainNonexistent;CAT:NONE;SFS:(13230040)(35042699022)(82310400026)(36860700013)(1800799024)(14060799003)(376014)(7416014);DIR:OUT;SFP:1101; X-OriginatorOrg: arm.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 03 Sep 2025 09:19:05.2516 (UTC) X-MS-Exchange-CrossTenant-Network-Message-Id: c15b0f0e-9cda-4af3-a170-08ddeacaedfc X-MS-Exchange-CrossTenant-Id: f34e5979-57d9-4aaa-ad4d-b122a662184d X-MS-Exchange-CrossTenant-OriginalAttributedTenantConnectingIp: TenantId=f34e5979-57d9-4aaa-ad4d-b122a662184d;Ip=[4.158.2.129];Helo=[outbound-uk1.az.dlp.m.darktrace.com] X-MS-Exchange-CrossTenant-AuthSource: DB5PEPF00014B97.eurprd02.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Anonymous X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem X-MS-Exchange-Transport-CrossTenantHeadersStamped: PAVPR08MB9723 X-Rspamd-Server: rspam02 X-Rspamd-Queue-Id: 1B76420005 X-Stat-Signature: 54g5o8ohq14s686irkdhkgstk1ksxyfz X-Rspam-User: X-HE-Tag: 1756891149-614462 X-HE-Meta: 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 QRMJpm3E 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 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: On 03/09/25 2:45 pm, Dev Jain wrote: > > On 03/09/25 1:38 pm, Wei Yang wrote: >> On Wed, Sep 03, 2025 at 11:16:34AM +0530, Dev Jain wrote: >>> Currently khugepaged does not collapse a region which does not have a >>> single writable page. This is wasteful since non-writable VMAs >>> mapped by >>> the application won't benefit from THP collapse. Therefore, remove this >>> restriction and allow khugepaged to collapse a VMA with arbitrary >>> protections. >>> >>> Along with this, currently MADV_COLLAPSE does not perform a collapse >>> on a >>> non-writable VMA, and this restriction is nowhere to be found on the >>> manpage - the restriction itself sounds wrong to me since the user >>> knows >>> the protection of the memory it has mapped, so collapsing read-only >>> memory via madvise() should be a choice of the user which shouldn't >>> be overriden by the kernel. >>> >>> On an arm64 machine, an average of 5% improvement is seen on some >>> mmtests >>> benchmarks, particularly hackbench, with a maximum improvement of 12%. >>> >>> Signed-off-by: Dev Jain >>> --- >> [...] >>> mm/khugepaged.c | 9 ++------- >>> 1 file changed, 2 insertions(+), 7 deletions(-) >>> >>> diff --git a/mm/khugepaged.c b/mm/khugepaged.c >>> index 4ec324a4c1fe..a0f1df2a7ae6 100644 >>> --- a/mm/khugepaged.c >>> +++ b/mm/khugepaged.c >>> @@ -676,9 +676,7 @@ static int __collapse_huge_page_isolate(struct >>> vm_area_struct *vma, >>>             writable = true; >>>     } >>> >>> -    if (unlikely(!writable)) { >>> -        result = SCAN_PAGE_RO; >>> -    } else if (unlikely(cc->is_khugepaged && !referenced)) { >> Would this cause more memory usage in system? >> >> For example, one application would fork itself many times. It >> executable area >> is read only, so all of them share one copy in memory. >> >> Now we may collapse the range and create one copy for each process. >> >> Ok, we have max_ptes_shared, while if some ptes are none, could it >> still do >> collapse? >> >> Maybe this is not realistic, just curious. > > Misunderstood your concern - you mean to say that a parent forks and > the children > VMAs are read-only pointing to the pages which were mapped by parent. > Hmm. I meant to say, writable VMAs with wrprotected ptes. Maybe after this patch, people can finally make some real use of the max_ptes_shared tunable :) > >> >>> +    if (unlikely(cc->is_khugepaged && !referenced)) { >>>         result = SCAN_LACK_REFERENCED_PAGE; >>>     } else { >>>         result = SCAN_SUCCEED; >>> @@ -1421,9 +1419,7 @@ static int hpage_collapse_scan_pmd(struct >>> mm_struct *mm, >>>              mmu_notifier_test_young(vma->vm_mm, _address))) >>>             referenced++; >>>     } >>> -    if (!writable) { >>> -        result = SCAN_PAGE_RO; >>> -    } else if (cc->is_khugepaged && >>> +    if (cc->is_khugepaged && >>>            (!referenced || >>>             (unmapped && referenced < HPAGE_PMD_NR / 2))) { >>>         result = SCAN_LACK_REFERENCED_PAGE; >>> @@ -2830,7 +2826,6 @@ int madvise_collapse(struct vm_area_struct >>> *vma, unsigned long start, >>>         case SCAN_PMD_NULL: >>>         case SCAN_PTE_NON_PRESENT: >>>         case SCAN_PTE_UFFD_WP: >>> -        case SCAN_PAGE_RO: >>>         case SCAN_LACK_REFERENCED_PAGE: >>>         case SCAN_PAGE_NULL: >>>         case SCAN_PAGE_COUNT: >>> -- >>> 2.30.2 >>> >