From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from SA9PR02CU001.outbound.protection.outlook.com (mail-southcentralusazon11013002.outbound.protection.outlook.com [40.93.196.2]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 366F033DED5 for ; Tue, 14 Jul 2026 05:34:53 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=fail smtp.client-ip=40.93.196.2 ARC-Seal:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784007295; cv=fail; b=XgFyXU1YdNPNNkbwTzt4x6K4oKixecMhbwGEnlLluMnjsszcB5UaYR/j5DKSVvEYgdaKebXZtqIqOY8861LduG8W/lUcl6cMsyUO0u4lfl3gcDxDBYsdctY3QyoIKt1kfHs9DXZOkHejz8ihfnqEQqB69RoLVayVRWyQQkEpHOI= ARC-Message-Signature:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784007295; c=relaxed/simple; bh=O/lInvv14huOcBlE5791ZvJUYXFhCtnXwRQZ96ZZksA=; h=Message-ID:Date:MIME-Version:Subject:To:CC:References:From: In-Reply-To:Content-Type; b=gKAEgfwKjnK5YdN2itPzFv7EGGfozQYaXvCUgEFe+Dwth2n+Z8XdLXv9V7XbrIn3tw2DM4tNFgIncfy3DYE5B5CP4xoc9TUOhWTxU6RGOzgFISUobWCofT0yFGocg1lNKkms7mInmdJ70qvOaOIyFKA0VPuQzIdXbAx9Tfc6c8g= ARC-Authentication-Results:i=2; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=amd.com; spf=fail smtp.mailfrom=amd.com; dkim=pass (1024-bit key) header.d=amd.com header.i=@amd.com header.b=m52KV0er; arc=fail smtp.client-ip=40.93.196.2 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=amd.com Authentication-Results: smtp.subspace.kernel.org; spf=fail smtp.mailfrom=amd.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=amd.com header.i=@amd.com header.b="m52KV0er" ARC-Seal: i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none; b=VemzUhGJDZdD8zhQCzBrnq2/zFprduYx8NykQprT8GwvZ8A5NeEiNwmm0vUkoGN9od0Iah05vm31YTophc0WK/xZ3IvHhNvwpDCFjBUo/K+DCLG4mvRvbh/u1UFvCQqrljAKDYHqaufmgC4sunaPPAYKhwsKmJLEh3SpFuv2ec3WtySq26H8jXn2+2ttk0kRgIFq70uS+1ZwzAJ+g1Gl9OgUe0BdNr8rCMta1b1qtamVvJUJu+dYnFZMXJ5pneFytwgBmapMDBsbP/5U9CXtxfKjkmLTSF3/2SxNnHmpyP6BJD1qF7XP1i2hIzjlmJKpZ85z2/EZb2vtvHS8RjyOQA== 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=Xns/PJeiu5/8JHBXMeg4+dKsO6xfQC2u+kuB0GRSZ28=; b=tYyW++eCjRtBS7y+caA8lFfU1ObptsWyH1+Y9TVgRiuY4sa3RaCG4d4ekNCBpOrIllfvnUTzI1KMkSA4iSoVObESLDclfamSs5CxXHUEq8ufEkBDyXt8mD7PFaJHS3DRnnsQYTXa0zsoFgObd3clAENzS8VeSI+t1FZNI9VIjc4SbyuNHz736Ilo44h+4/w7biIaAQRt6p+otntcoES3zyASS5wNDwwggPTdaDBuMqLwWE0+U1FwuSAeIWnYZvd63X4gDFswN2QejGAsbTM1GvTdNdcQH9Znc1uAuenrbBP8YBJQQqj757tZKzVh9ZIOXAGBlVX9/VbrK4XdUvut8A== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass (sender ip is 165.204.84.17) smtp.rcpttodomain=linux-foundation.org smtp.mailfrom=amd.com; dmarc=pass (p=quarantine sp=quarantine pct=100) action=none header.from=amd.com; dkim=none (message not signed); arc=none (0) 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=Xns/PJeiu5/8JHBXMeg4+dKsO6xfQC2u+kuB0GRSZ28=; b=m52KV0ervrCIQ2iksoQTIqKJ7ZosO9Ez0KO/SBn0MqvSOIB7Vl8jM5pVhHjKi9WdTvCBk+pIZUsNlKAu0Mlqzzv+C38Hm6VJRX6X38ejFCwHJF8Ma5dt0nbP3nsufPyjuIn/G8/V3tVCDuHxNDi9R8OZas83bCGerHNns3uJ5ko= Received: from SJ0PR13CA0219.namprd13.prod.outlook.com (2603:10b6:a03:2c1::14) by IA0PR12MB7776.namprd12.prod.outlook.com (2603:10b6:208:430::15) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.21.202.19; Tue, 14 Jul 2026 05:34:49 +0000 Received: from SJ5PEPF000001D4.namprd05.prod.outlook.com (2603:10b6:a03:2c1:cafe::ad) by SJ0PR13CA0219.outlook.office365.com (2603:10b6:a03:2c1::14) with Microsoft SMTP Server (version=TLS1_3, cipher=TLS_AES_256_GCM_SHA384) id 15.21.223.9 via Frontend Transport; Tue, 14 Jul 2026 05:34:48 +0000 X-MS-Exchange-Authentication-Results: spf=pass (sender IP is 165.204.84.17) smtp.mailfrom=amd.com; dkim=none (message not signed) header.d=none;dmarc=pass action=none header.from=amd.com; Received-SPF: Pass (protection.outlook.com: domain of amd.com designates 165.204.84.17 as permitted sender) receiver=protection.outlook.com; client-ip=165.204.84.17; helo=satlexmb07.amd.com; pr=C Received: from satlexmb07.amd.com (165.204.84.17) by SJ5PEPF000001D4.mail.protection.outlook.com (10.167.242.56) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.21.223.9 via Frontend Transport; Tue, 14 Jul 2026 05:34:48 +0000 Received: from [10.128.124.134] (10.180.168.240) by satlexmb07.amd.com (10.181.42.216) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.2562.41; Tue, 14 Jul 2026 00:34:40 -0500 Message-ID: <442897a7-7b17-4025-bfb0-fe2db8d64198@amd.com> Date: Tue, 14 Jul 2026 11:04:37 +0530 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 0/6] mm: batch rmap walks during large folio migration To: Andrew Morton CC: David Hildenbrand , Lorenzo Stoakes , Rik van Riel , "Liam R. Howlett" , Vlastimil Babka , Harry Yoo , Jann Horn , Lance Yang , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Zi Yan , Matthew Brost , Joshua Hahn , Rakie Kim , Byungchul Park , Gregory Price , Ying Huang , "Alistair Popple" , Karim Manaouil , "Frank van der Linden" , Kinsey Ho , Wei Xu , Bharata B Rao , David Rientjes , Dev Jain , , References: <20260712-migrate-rmap-batch-v1-0-872a734431d1@amd.com> <20260713190516.0c669b5207667c893a9c0938@linux-foundation.org> Content-Language: en-US From: "Garg, Shivank" In-Reply-To: <20260713190516.0c669b5207667c893a9c0938@linux-foundation.org> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 8bit X-ClientProxiedBy: satlexmb07.amd.com (10.181.42.216) To satlexmb07.amd.com (10.181.42.216) X-EOPAttributedMessage: 0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: SJ5PEPF000001D4:EE_|IA0PR12MB7776:EE_ X-MS-Office365-Filtering-Correlation-Id: 9599a419-6e80-4a64-fbf0-08dee1699ee6 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|376014|23010399003|7416014|82310400026|1800799024|36860700016|22082099003|18002099003|4143699003|56012099006|11063799006|13003099007; X-Microsoft-Antispam-Message-Info: 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 X-Forefront-Antispam-Report: CIP:165.204.84.17;CTRY:US;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:satlexmb07.amd.com;PTR:InfoDomainNonexistent;CAT:NONE;SFS:(13230040)(376014)(23010399003)(7416014)(82310400026)(1800799024)(36860700016)(22082099003)(18002099003)(4143699003)(56012099006)(11063799006)(13003099007);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: t3+H5k2DcQAHS3rLgULPx5Q3s1l5Xy2opJozQ4RoI3XudMDE6waFE/SBnNIrsp0yOdFfbpJHH1EhT6buL7r+v1NENEBv1VUT7iLFMKmlkqak6vScBr1dS1vKxjOe1uX+SapcrzYqO3zSM/FOZOUWQeZKyRb1pWUiCaWCbjZT8jmcUtVAik0uhIvl2ERmtCJ8x30IHUvs5dcFubJ0XLPXp1yqvck52QUacvEDTT5dUVPpMa2AQtfuusz3jSh+dULGX0IjM8KpY0dR96uzJZIL3JBRkaWqtTROqFf7RpMhh1ys21CeDnd8F44Ckjpl5i0ekS2MKpMcJLLDoED/LSo2wfAcmb4Y3cLnGdHO61Rk0aYp2TcvNXO6LjOtEqSxQcTs8hwI9zxDaOASONJIq63j5RA9aaeoVVEuMMDVnvuimWG4/S12ogaO7CEGOjUYyaYO X-OriginatorOrg: amd.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 14 Jul 2026 05:34:48.5669 (UTC) X-MS-Exchange-CrossTenant-Network-Message-Id: 9599a419-6e80-4a64-fbf0-08dee1699ee6 X-MS-Exchange-CrossTenant-Id: 3dd8961f-e488-4e60-8e11-a82d994e183d X-MS-Exchange-CrossTenant-OriginalAttributedTenantConnectingIp: TenantId=3dd8961f-e488-4e60-8e11-a82d994e183d;Ip=[165.204.84.17];Helo=[satlexmb07.amd.com] X-MS-Exchange-CrossTenant-AuthSource: SJ5PEPF000001D4.namprd05.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Anonymous X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem X-MS-Exchange-Transport-CrossTenantHeadersStamped: IA0PR12MB7776 On 7/14/2026 7:35 AM, Andrew Morton wrote: > On Sun, 12 Jul 2026 07:38:46 +0000 Shivank Garg wrote: > >> Performance: >> >> AMD EPYC ZEN 3, 2-socket system (1 node per socket). >> move_pages() migrating 1 GB from node 0 -> node 1, throughput >> in GB/s: >> batch- batch-restore + >> folio vanilla restore unmap restore% restore+unmap% >> 4K 2.98±0.09 2.95±0.07 3.06±0.05 -1.0% +2.6% >> 64K 6.16±0.09 6.24±0.08 7.80±0.08 +1.3% +26.6% >> 256K 6.85±0.06 6.85±0.09 9.54±0.19 +0.0% +39.3% >> 1M 7.06±0.09 7.17±0.09 9.89±0.06 +1.5% +40.1% >> 2M 10.97±0.17 10.67±0.13 10.69±0.15 -2.7% -2.6% >> >> In plain migration, the folio copy itself dominate the cost, so these rmap walk >> savings are only partly visible end-to-end. >> When the folio copy is batched-copy and offloaded to DMA engine [1], the copy is >> no longer the bottlneck and rmap-walk batching translates into much larger gains: >> >> This series + [1], DMA Offload on PTDMA (DCBM), 16 channels: >> >> batch-copy >> folio vanilla -offload(dcbm) dcbm+restore dcbm+restore+unmap >> 4K 3.36 ± 0.10 4.16 ± 0.18 4.10 ± 0.14 4.12 ± 0.13 >> 64K 6.16 ± 0.47 9.63 ± 0.23 10.00 ± 0.33 14.63 ± 0.14 >> 256K 6.70 ± 0.09 12.98 ± 0.18 13.52 ± 0.15 32.30 ± 0.65 (2.38x) >> 1M 6.99 ± 0.02 14.32 ± 0.67 14.84 ± 0.17 38.97 ± 1.03 (2.62x) >> 2M 10.74 ± 0.29 64.25 ± 1.48 65.36 ± 1.00 64.97 ± 1.75 > > Well dang. > > Thanks. I'll await reviewer input on this series. > > Sashiko said things: > https://sashiko.dev/#/patchset/20260712-migrate-rmap-batch-v1-0-872a734431d1@amd.com Thanks Andrew. I'm working on this and the syzbot reported issue. Best regards, Shivank