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 E1E9EE77188 for ; Mon, 6 Jan 2025 09:15:15 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 6ACD56B0089; Mon, 6 Jan 2025 04:15:15 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 65B266B008A; Mon, 6 Jan 2025 04:15:15 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 4FC1E6B008C; Mon, 6 Jan 2025 04:15:15 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0010.hostedemail.com [216.40.44.10]) by kanga.kvack.org (Postfix) with ESMTP id 368856B0089 for ; Mon, 6 Jan 2025 04:15:15 -0500 (EST) Received: from smtpin24.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay09.hostedemail.com (Postfix) with ESMTP id D93F880300 for ; Mon, 6 Jan 2025 09:15:14 +0000 (UTC) X-FDA: 82976468148.24.D574D6F Received: from NAM10-BN7-obe.outbound.protection.outlook.com (mail-bn7nam10on2055.outbound.protection.outlook.com [40.107.92.55]) by imf18.hostedemail.com (Postfix) with ESMTP id E34E81C0011 for ; Mon, 6 Jan 2025 09:15:11 +0000 (UTC) Authentication-Results: imf18.hostedemail.com; dkim=pass header.d=amd.com header.s=selector1 header.b=XjW7pGuV; spf=pass (imf18.hostedemail.com: domain of shivankg@amd.com designates 40.107.92.55 as permitted sender) smtp.mailfrom=shivankg@amd.com; dmarc=pass (policy=quarantine) header.from=amd.com; arc=pass ("microsoft.com:s=arcselector10001:i=1") ARC-Message-Signature: i=2; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1736154912; 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=M3XKD5yKynyvb4en8m/p8QcnkhvCGj4NLP11LtKttFk=; b=zU+Y/7yF8OVNT/gtLb8/gGfKuouVvUfKm1bLXxno4ijpRakFyEOwBCjSkXWTlyDge4R02G V0uRDDtIsgZ8TuwFubuPDv4iBQPWbOURrug/J89Q9y7dUOv3FHZDMKxzq2K4QaoHdus8+l vC2YzTX0u4ry0y/0gu0nvCQ2QsiNKwc= ARC-Authentication-Results: i=2; imf18.hostedemail.com; dkim=pass header.d=amd.com header.s=selector1 header.b=XjW7pGuV; spf=pass (imf18.hostedemail.com: domain of shivankg@amd.com designates 40.107.92.55 as permitted sender) smtp.mailfrom=shivankg@amd.com; dmarc=pass (policy=quarantine) header.from=amd.com; arc=pass ("microsoft.com:s=arcselector10001:i=1") ARC-Seal: i=2; s=arc-20220608; d=hostedemail.com; t=1736154912; a=rsa-sha256; cv=pass; b=taU4Zn+2bH3xgF/Ew0vMn49UxlnfoU5Lum2o8uyrJCQql3mxz68O73vG6QMEvYTNx9GZsR bdD4wx+TTs/OOLQGV3QaN+kyoTiZbHWhRAnvTlDnUyCqiVOU6mXtoDcjXe4Prm7Mp1VmW5 Fb3lvImykzJ3cd6AdQMDi2zQAvKnR3M= ARC-Seal: i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none; b=tFXwkGB4JxBlWW7abfV3KRE9+rcARKWpgCsx53OmBO8mGI+SsZpCri+yyckAg7A0pXlXsEeW3UbeZIwoSXJSLJscNGU1G9rWhpEzkDpXyLtsoWqixlYets9PmNX7npw+3JvfT3nNmGBvZqb3S7G8vGpzwwGM6zijoUnQzQVkxW2fud946u8SBKbEldVbPQcKdB/CCCVPulEYaL55vnbn19xQkQkUA4RmRLYVb9xfjAP1qP2ORoVp+2nRwuqAcm8iIyiEL7yZwFUZbbxaum5YZrMbjbbHe1NvmBrvBjof6PRMaQXKyODnRCjMh+mQAeGlYUhtKptZWwW70P4YL6vzeA== 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=M3XKD5yKynyvb4en8m/p8QcnkhvCGj4NLP11LtKttFk=; b=b33SBuYYNSXXcw09qg/FHSLRaix2EPqh8xlxagTYx7FGrhRaN37Poyn/QJt9JhdsgTkdCa7sXjSsbVnayTvO8r/bWHdtNXRvNzK5+yTtsAk0ggvG67L3YsxxyFewOtj9Y8ETHXdD2pDj2Zp5xvp0p0IRcFI21/9AFIfLL69BSE0i3RkEb6TiCH05Tc8z6mBREX2fd5pGadXYK+OJ8nxSpCvl9ssoOl5eF4BLuwopod2JnJBvEAsmD1a3CCtjq3RtYlz72aiiiCgZzP/udoljxfmWOxaFMts/bkpT/btc1mXkBMUnt6zIvnlSt3z9hHF0r/QsAws67wXRqMEwzkMOwg== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=amd.com; dmarc=pass action=none header.from=amd.com; dkim=pass header.d=amd.com; arc=none DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=amd.com; s=selector1; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=M3XKD5yKynyvb4en8m/p8QcnkhvCGj4NLP11LtKttFk=; b=XjW7pGuVge4wpMiGFVhBdtQV2OSFtEedo8GiMkdC7lUzAAbMdCnsGKABg1PwwDerMuQNeeOFGsI7TwAmfIq3fFHtlAP0syZwaL56IG9OiregO0eZGtUOQtvWKhwDhQTiEJOFhX2fSgUwa1GzHIB78QBdaAtBvC/eRLwr6yjQL4I= Received: from CH2PR12MB4262.namprd12.prod.outlook.com (2603:10b6:610:af::8) by BL3PR12MB6476.namprd12.prod.outlook.com (2603:10b6:208:3bc::8) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.8314.17; Mon, 6 Jan 2025 09:15:05 +0000 Received: from CH2PR12MB4262.namprd12.prod.outlook.com ([fe80::3bdb:bf3d:8bde:7870]) by CH2PR12MB4262.namprd12.prod.outlook.com ([fe80::3bdb:bf3d:8bde:7870%2]) with mapi id 15.20.8314.015; Mon, 6 Jan 2025 09:15:05 +0000 Message-ID: <78e27ff3-2cb2-4007-ac6f-b4ac82cdc6da@amd.com> Date: Mon, 6 Jan 2025 14:44:51 +0530 User-Agent: Mozilla Thunderbird Subject: Re: Slow-tier Page Promotion discussion recap and open questions To: David Rientjes Cc: Zi Yan , Aneesh Kumar , David Hildenbrand , John Hubbard , Kirill Shutemov , Matthew Wilcox , Mel Gorman , "Rao, Bharata Bhasker" , Rik van Riel , RaghavendraKT , Wei Xu , Suyeon Lee , Lei Chen , "Shukla, Santosh" , "Grimm, Jon" , sj@kernel.org, shy828301@gmail.com, Liam Howlett , Gregory Price , linux-mm@kvack.org References: <6d582bb6-3ba5-1768-92f2-6025340a3cd4@google.com> <9093302B-95A9-4133-A0E0-75A47CE4336F@nvidia.com> <1c424899-d394-452f-9e13-d8cf77660c4a@amd.com> Content-Language: en-US From: Shivank Garg In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-ClientProxiedBy: PN3PR01CA0066.INDPRD01.PROD.OUTLOOK.COM (2603:1096:c01:99::15) To CH2PR12MB4262.namprd12.prod.outlook.com (2603:10b6:610:af::8) MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: CH2PR12MB4262:EE_|BL3PR12MB6476:EE_ X-MS-Office365-Filtering-Correlation-Id: 5151013d-6a44-4d9a-0777-08dd2e329b59 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|366016|1800799024|7416014|376014; X-Microsoft-Antispam-Message-Info: =?utf-8?B?anE5N1ZVbVhyeCtDM3pWSVl0MEIycHk2Wk1uVElaZUxDTTJYUGkyRE9pTVZt?= =?utf-8?B?Rk5uYjdWL2h0WHNQK0xXNkFmcUZacjNOU3RqZ0tOVHpITURidFNTUXhjZEFj?= =?utf-8?B?T3NnQitKd1QyU2tOMjdEUkl0ZElQd0t2YnlqSy9mUHJKSW92djEyQkVqNUg4?= =?utf-8?B?OW5qUW1WM2kwSDFLcTZKWjBpUXI5Qk1YejRFSHFNVzB0bHR3MmF5V2FrMHZO?= =?utf-8?B?TWdOZ1FLUU1uUlpsNlZpVEdkRUJsS2ttaVB0NERXWFFjV2J2eE8rZmdmdlRm?= =?utf-8?B?elYrT2F2c3hRZWluK2pSbW40dDJPdUNTUUlQRGgrcExxdmRHQXBoUHNaeXhU?= =?utf-8?B?NkhWc2RxdkNIa2NvYWR0K1RaUlRrcUJiOWk0MjVOOVJXalc2SWRqbGl4dDFo?= =?utf-8?B?cVNFb0s0dmljNEg4cksxUlJsYnpHR3dRMDY4RjJPaEgxYUxuRytiUEl0amtZ?= =?utf-8?B?b1ZkWGNXdjJIUWo0Y2N4NDMyaEs1c1laZkRBWWt5U3pJWHk0dVhiS2s0YTNQ?= =?utf-8?B?cWI0TVVQVmxwcVp6MGVXTTQ4KzlXR245bm5ORGlyZEpzbGw1bCtnbFYybWF1?= =?utf-8?B?bk41LzV2dUhmUjBpTk05MEJqaDNRS29PQmxWaVlYQUtGcmlVSlRlUmZYSExs?= =?utf-8?B?d2VZeW92UDJPQ1U3NTRKOWxhdEQrMjkya0lZRmVzSCs2b0M2czNhRUJuaXM5?= =?utf-8?B?V2FFczNqdXJUaG1WSFpNZG55bzFJMG5BRTB4UHZ5Yk1tVTV5djJVR21nV2hx?= =?utf-8?B?WDlGemZkLy9lbzZreVU2K0RFcGdkMnFXS3Zlb0RXZlVMOTNBVnBhZzFLbWxp?= =?utf-8?B?MmdmYTJ1K3BRZXRIQ1c4WkVZanFLWXNVbW51cG5kOW5FdjZKc0ZaSXFpUkhX?= =?utf-8?B?aXkrZzZBMjRVRWhzYi9SbUdVQmRyQWEyTlBUWmJzYmtnUWVoRnZ0dDdudVMv?= =?utf-8?B?d3lFOEpaS1gyYkpNR0xlcG5KQUVheEc5U0lWVUhxZEp0NnpmV0pUTFBUeHNZ?= =?utf-8?B?L2drODhNU2toa0gxWXJ0Sms2b00xbUh3OXRzU2sycnhMWFRCUm04bmlPRWRZ?= =?utf-8?B?UzA2a3pubExCTm5Pb1RudnNZbC9odFFaOEhaRjMveUgrTkVjdGhsY1VkTmwy?= =?utf-8?B?VHFsbTliTWpML2syZ0FTTTI5VU1xYkFHeGdRejkvQXROYWc1UDRGcXpaeFd2?= =?utf-8?B?T1pMNElCQTVOWGpiT2hZUEJDSjZyWWM2N0Z6TVBnTFcrVHpLTmt5RnhWNm9w?= =?utf-8?B?UmF1Mys2dk4yRU9wZWtqa2VjbjczaUZaVjNEV2dRaTcyc2VkZnhCVEZsUGJv?= =?utf-8?B?MFV2QkxoSGRHWWIrSjJJNHJrOGRyNFFpRFdWMjBPckFFbng5SkJjTTd5eUVE?= =?utf-8?B?MDk4TW9NVXQzWXJRRUFJcVNLekV3aFpIZ2dUc1dsYXJ5cWlxbS9WckE4K2Rv?= =?utf-8?B?ZUNCcmlVdU1EN0xhUlkwbmJQSDkwWlJtVHAyaEpvUlEzc0tLVFZBemVZeGw2?= =?utf-8?B?d1dzWVBnK1p6WXo4aEVLdm45dkQrLzV3Wk91Ym16L20rTW1sL1V2SmorUEU2?= =?utf-8?B?Zk9LaUZnOWNPREpvdGU0QXhHNEs1TCsrWEZhQ1BGZkZPSmx5Z0EvbkJoMWdU?= =?utf-8?B?bDNXOGJHQmJEbG41bFhDSU0rRUl4MzlGdDNJZmlPNjRkSWdBVnlKbld2cXZH?= =?utf-8?B?SWlwRlphVDFvNnc4Q1hnT0pScmtkTlg5am5BMHhUd3VvRDR5K1daL3g0TE44?= =?utf-8?B?SVZhd25DUDhpWDQ4Q3NjSEYzVW5Md01sc1d1SklkZjNGN0VLbk9kRGFoMUVG?= =?utf-8?B?UHNkTTN6ai9LZlVsUTBIcW1HbDhWZW5PZUo1Q2RoOTRNRGpqTStrWEM3M1Fp?= =?utf-8?B?MkgzelY0SFFONTlEdyt4TDhPNWFzUG03U3NrL2M0RitMSGc9PQ==?= X-Forefront-Antispam-Report: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:CH2PR12MB4262.namprd12.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230040)(366016)(1800799024)(7416014)(376014);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?utf-8?B?eTV2MWZGa0o5TVRrVDJtMVJtU28wYlo5WFNSV1BnT2pyWHZmQ0VSVzMyUGZL?= =?utf-8?B?T3JxWVFkNXBZWi9oZ3ZyZ2JldXRNZFg4NHhodTBtYkpPdE5sZ0tmb1BJVng0?= =?utf-8?B?TitxckZQeEpTdHZ4WWNqamJBWnVsNjh0VDZDSFF6UlRKalhPVWovcVZrRFJy?= =?utf-8?B?SDRBN2p2aWh6VHpwcFZjM3lNTWtrOS9iSlVlVnNlRU91eG9adEtWYmxnaW5q?= =?utf-8?B?ZlptajV5WmNJT0hZNEc1Y2FxZnphOWRxVUtSMWphRFcyZ1hNN203MnZqU2h4?= =?utf-8?B?aDRvVHJISndJVzU1WXdJaGxBb0hUejlwZGFyd2lUNjMxRHM2R0dhT0ozTk1a?= =?utf-8?B?ZWdaK2svTm1SaHJnNDJSUW5lQzlacUlETmptemozL0RpU2F0dHIwV21wd0J0?= =?utf-8?B?RFRqcE1FSWk1Yng0aDFtTi9qTE8xRmZVSGtJV3l5QlRTTEE2dVdqTXUyZzJO?= =?utf-8?B?bDc1ZmlkeW9ja0RaRVlhNnFpZ2FUc0pQWVZ0WkN2enVlSk5yZkVFY1ZCeUJl?= =?utf-8?B?V3dSRUl1YTAzTjFQc1ovdG5taHcyalRuREpjbFhzbkpSbG5BelM0WElVM3l3?= =?utf-8?B?QXlVcEJSVUJvSG5Bb3grVndFa2g2YWtTQTRBb2pLM1hDdXY3amhJZHRSYmNz?= =?utf-8?B?RnJJNWJiL1ZCQzJVWE5YWTlLM2YyQzF2NGxoVmIwYWpHQWJIbHA3djltMjIx?= =?utf-8?B?cWJ5WmlWUUV6ZnhQU2NDVnRYcFl1U2RRbE5rMmlyYkdKeVRKT2lPelVwZUYy?= =?utf-8?B?YjVPNFhzaGtaYk02TlRSdHlJcU5IdlBUVElmZkhNc2drSGNUSmcvQkwveHU2?= =?utf-8?B?b0cveUx6aTNpQTMwL1FRdUxsbjRVNGtWWm9HdDFuU3FzcTdVRU12eS9ucUZZ?= =?utf-8?B?YlFZRTQ1SlBXdnJrVStySDZlMS8veEtENEMxNGRxU0NBSmVXd0RVQklQNW5H?= =?utf-8?B?WXhtZnR4ZEd2WnRqMkhBdGJrZnpRRVpnWHNwZ2VmUGRVTmp0V3NyN1ZXei9B?= =?utf-8?B?RGQzWG9CZm0wNU1HQTlzaGZXMHJJUTJIQ2F1UEpXMmprRkVCZE5jWGxIYk12?= =?utf-8?B?VkFiMDFMcUMxaGYwUitid2U2MjRWdjJzS3JiWTdQcG1aYldzbjN1WU9RazFZ?= =?utf-8?B?SWVicHhmWWwxMnlVRnhlMUdOTlpZeU94c25WS09vMW1iMHE3SkZQdk54d1A1?= =?utf-8?B?S2g2enY0ZnNqUzVsMEZVTnZ1WEE5YU5pRExqbklqR3FzSDA5c1U2ZVc4Q2lC?= =?utf-8?B?RE1nck1qUFBKaVQ4d0hRVWxRY1ZtQjBpT243NTdzc0tiQ2RpaDhHZ2lHbG9h?= =?utf-8?B?ZTFhWVYyYnluL2k3bW4yWWtscHo3Z2dqZWM4cTBTOTI2QXd3VmdTWVhKeXRG?= =?utf-8?B?WnlkRXJIMjJJRVdwTXU4WG41VEFBcExMRDBxbjdQNVFPNjJpNTd0dTBlc2xD?= =?utf-8?B?QWNMblRobkVMa1ByaUY1SzZMYnZ6aVZWR3d5LzAyMDhqL051M1FiNGd1eWNv?= =?utf-8?B?R0Rmc1Y3V3J1dHdpdXlzZWNPOVNOU3l1Y3c3b3JiTE8zTE1tM1M2RjhFMy9m?= =?utf-8?B?OXJENSt0azFBbmZnRG15ZnMyWWtzYXlSVDJ3aGRjR2RCZkVpSjRjdjFMQkdG?= =?utf-8?B?U2VRbVZZQUppcUZjTXJZUDZoSFh2clVEaGRWaXM5TzJGMVRoUENKNkYrcUlx?= =?utf-8?B?UlRYNzN4a3EySms2NGY0dEZxQ1lJQUpEcStFOEVocnUxY0RiQ3IraHF2SGRD?= =?utf-8?B?dHNvY2U0TzkzWHBuTTMzYkhtSkNhT2Y0UmhPTjVWMmFGc1gxcHRLTGZFT0NL?= =?utf-8?B?TjJrK2UzSTlRUmZrdEVlOXp2eHdma01UcXpGRVJPY0xGRVNqV1JBdmJKcElD?= =?utf-8?B?UWVWemVpMWNlZmN2TnFrMythQ3VQbUZVRUt5MTR6RWRFbWpuY1pkRjBwVTZw?= =?utf-8?B?NDlVelY2VXZrN0JXSkxMaXE4WlFpZWs2Q0cyYlkyaSs5UERzOS9CK2RtTVNT?= =?utf-8?B?NHNWZUNLeDg4T05XejF0dEhYR25GRDlCb0F4YTZFdjkrbmZnZ3UrTFZmeHBR?= =?utf-8?B?ZXdRc004OWZOSXhwZ1JBcTRQUEhHUWRWTm1kNUs2elhyMTF1OU9wZHFpbnBo?= =?utf-8?Q?jVXnUEFD53BHmMxzhUk9xVZqb?= X-OriginatorOrg: amd.com X-MS-Exchange-CrossTenant-Network-Message-Id: 5151013d-6a44-4d9a-0777-08dd2e329b59 X-MS-Exchange-CrossTenant-AuthSource: CH2PR12MB4262.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 06 Jan 2025 09:15:05.0837 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 3dd8961f-e488-4e60-8e11-a82d994e183d X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: sjbSnFNtddDjXH9x9bymKJDpTEOaKx/vt1yeK+IYFDwqnnH4d+OjtAg8kONr5M8WV+WHzfnVJ4w0PhDJErJ1xQ== X-MS-Exchange-Transport-CrossTenantHeadersStamped: BL3PR12MB6476 X-Rspamd-Server: rspam06 X-Rspamd-Queue-Id: E34E81C0011 X-Rspam-User: X-Stat-Signature: frxf9ozu9assofmcth66yg43oeoay5dd X-HE-Tag: 1736154911-188566 X-HE-Meta: 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 hOPM5BN0 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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 12/30/2024 11:00 AM, David Rientjes wrote: > On Thu, 19 Dec 2024, Shivank Garg wrote: > >> On 12/18/2024 8:20 PM, Zi Yan wrote: >>> On 17 Dec 2024, at 23:19, David Rientjes wrote: >>> >>>> Hi everybody, >>>> >>>> We had a very interactive discussion last week led by RaghavendraKT on >>>> slow-tier page promotion intended for memory tiering platforms, thank >>>> you! Thanks as well to everybody who attended and provided great >>>> questions, suggestions, and feedback. >>>> >>>> The RFC patch series "mm: slowtier page promotion based on PTE A bit"[1] >>>> is a proposal to allow for asynchronous page promotion based on memory >>>> accesses as an alternative to NUMA Balancing based promotions. There was >>>> widespread interest in this topic and the discussion surfaced multiple >>>> use cases and requirements, very focused on CXL use cases. >>>> >>> >>>> ----->o----- >>>> I asked about offloading the migration to a data mover, such as the PSP >>>> for AMD, DMA engine, etc and whether that should be treated entirely >>>> separately as a topic. Bharata said there was a proof-of-concept >>>> available from AMD that does just that but the initial results were not >>>> that encouraging. >>>> >>>> Zi asked if the DMA engine saturated the link between the slow and fast >>>> tiers. If we want to offload to a copy engine, we need to verify that >>>> the throughput is sufficient or we may be better off using idle cpus to >>>> perform the migration for us. >>> >>> >>>> >>>> - we likely want to reconsider the single threaded nature of the kthread >>>> even if only for NUMA purposes >>>> >>> >>> Related to using DMA engine and/or multi threads for page migration, I had >>> a patchset accelerating page migration[1] back in 2019. It showed good >>> throughput speedup, ~4x using 16 threads to copy multiple 2MB THP. I think >>> it is time to revisit the topic. >>> >>> >>> [1] https://lore.kernel.org/linux-mm/20190404020046.32741-1-zi.yan@sent.com/ >> >> Hi All, >> >> I wanted to provide some additional context regarding the AMD DMA offloading >> POC mentioned by Bharata: >> https://lore.kernel.org/linux-mm/20240614221525.19170-1-shivankg@amd.com >> >> While the initial results weren't as encouraging as hoped, I plan to improve this >> in next versions of the patchset. >> >> The core idea in my RFC patchset is restructuring the folio move operation >> to better leverage DMA hardware. Instead of the current folio-by-folio approach: >> >> for_each_folio() { >> copy metadata + content + update PTEs >> } >> >> We batch the operations to minimize overhead: >> >> for_each_folio() { >> copy metadata >> } >> DMA batch copy all content >> for_each_folio() { >> update PTEs >> } >> >> My experiment showed that folio copy can consume up to 26.6% of total migration >> cost when moving data between NUMA nodes. This suggests significant room for >> improvement through DMA offloading, particularly for the larger transfers expected >> in CXL scenarios. >> >> It would be interesting work on combining these approaches for optimized page >> promotion. >> > > This is very exciting, thanks Shivank and Zi! The reason I brought this > topic up during the session on asynchronous page promotion for memory > tiering was because page migration is likely going to become *much* more > popular and will be in the critical path under system-wide memory > pressure. Hardware assist and any software optimizations that can go > along with it would certainly be very interesting to discuss. > > Shivank, do you have an estimated timeline for when that patch series will > be refreshed? Any planned integration with TMPM? Hi David, It's definitely interesting for us to get it working with SDXI. I'm going to try it out. Thanks, Shivank > > Zi, are you looking to refresh your series and continue discussing page > migration offload? We could set up another Linux MM Alignment Session > topic focused exactly on this and get representatives from the vendors > involved. > > Thanks!