From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from PH0PR06CU001.outbound.protection.outlook.com (mail-westus3azon11011010.outbound.protection.outlook.com [40.107.208.10]) (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 C338935B645 for ; Fri, 28 Aug 2026 04:16:47 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=fail smtp.client-ip=40.107.208.10 ARC-Seal:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787890609; cv=fail; b=CvXTSqOVSNtFNfcinBKFasAnqMj4nYSz75XFi+qT7AimqvCZU72/nBP9L+fzm8S1KANzXcnsipSim9G4VsRM7Il5dbTi7kFU7ElzLyuG6/2QI5aSIsdGsYt2rHtSk5oOKj7KFoXyK7VOF18m0xgfmSRg1+lEkOe2ZOOJk7gYsos= ARC-Message-Signature:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787890609; c=relaxed/simple; bh=Mzaf1w3SUpqS88VVgGYy+6LX3xJmC3SxsTRXyGLImFA=; h=Message-ID:Date:Subject:To:Cc:References:From:In-Reply-To: Content-Type:MIME-Version; b=riA4CfwCJ3HJJFFNABAWlEDl4h5BbBRJ00D+jwFHdXis0N9Z630JZ2yr179kswBjIXqz2Y45jS06tTIDo1aXGgMZ/DUUCUdGcqACjh9dG+X75llitBFBFdV+XBI+K08DmgyyGYyZmlBHzN0HwYM8MAaj6LZu3pv0dmAG3ulQlrc= ARC-Authentication-Results:i=2; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=nvidia.com; spf=fail smtp.mailfrom=nvidia.com; dkim=pass (2048-bit key) header.d=Nvidia.com header.i=@Nvidia.com header.b=MMG1hjip; arc=fail smtp.client-ip=40.107.208.10 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=nvidia.com Authentication-Results: smtp.subspace.kernel.org; spf=fail smtp.mailfrom=nvidia.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=Nvidia.com header.i=@Nvidia.com header.b="MMG1hjip" ARC-Seal: i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none; b=oyMrB0Dhhyho/PJyanqfpNE0V+DVMpYAl9ifW09R50gxUcSGMRrkT0WfhNLHUSmbUu/hbJOoD0AKLVL+Zr/xR4epsM8b8pfb2srmCh5cH/0aVHyoAzInrly9jRw7K5DuAOp6YYdzJHXwKq8AdnK2iVmDPUSQfsXM458rC+37fAvMOUs+TetpPMhTo3jXgV/xfpNsL3nE1wPx+ISMme0VcE0PpS60rWNuVqHYnQ+UskXHt2Dc9vcMfiV+ghSQCnxryK/zkOA6dZJVWu7w1QX04d/xlesOh9AHpsTswncyUUxhROagb60wctI7hgSBK5fedDz+JpFW92Hm9Y14yRCRbA== 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=K051lvoOXuKBKIvlTSjJybYPZ4jUeTpY9bWOPLd57LU=; b=ilWb5PBn02oABhIX7UnA5viRin8zx4gTwU7bFs6S0tF+Rb+6Uk33t3U+8gz/r1eeEgzQj9rf3hdmYg2GtHtr/K8qCB9y45taHn6luHlfZAuuR5SAACbDmL8q6JZQM9eIZfVzDRj8m1Z92Xon7R6M+AoS6x0gaJvP6MSiBIdrPKk8hwWEDFKFAWyCvmODktr0XT4ibERxl/nwfb5tnFQFdP+gl82932YALnez9+GH4ORKIlP9zQT91wvjA+8QEVN3eGw2UR1kWvGiPAQgQ20el80tGP7jGWQKRuF5bJUT9L0VXk8FyU2FXunOuQnYq9xoNgAR+wHU4jaQd8E7XI6DnQ== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=nvidia.com; dmarc=pass action=none header.from=nvidia.com; dkim=pass header.d=nvidia.com; arc=none DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=Nvidia.com; s=selector2; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=K051lvoOXuKBKIvlTSjJybYPZ4jUeTpY9bWOPLd57LU=; b=MMG1hjipuyQBtLVjqw8FTR2GyarcXnUho7BALkErMySNsLtUpH7C1lriY3N3Badk8+3lpeMvY+KeVWCMnSOwpEo2HiLubcX8ABvRaGzrTwMluH0YzgWlc2vT1sy/ta2ouzpfcKjzAV0lwCe9omKXf4xrjhzSWXkGwhOqXSKeC2Lu1Zxn0Lr8p+92KqGewxkly7GTe3CCbqy+0EXjiXFGbKHZBnDB8E9IjGmUqdZtHdLXKDFFozBzVB6/sWAk13NUrEbW49e5LUoY3jn4/y/mko62b72PHW7vGiUWONTRZa3Kwm6c+KZr4zPGkFGmqyO9i0ARMFCdE05RaijVVs22EQ== Authentication-Results: dkim=none (message not signed) header.d=none;dmarc=none action=none header.from=nvidia.com; Received: from CH1PR12MB9670.namprd12.prod.outlook.com (2603:10b6:610:2af::6) by CY5PR12MB6057.namprd12.prod.outlook.com (2603:10b6:930:2e::17) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.21.360.6; Fri, 28 Aug 2026 04:16:44 +0000 Received: from CH1PR12MB9670.namprd12.prod.outlook.com ([fe80::416:ea1f:d17b:2811]) by CH1PR12MB9670.namprd12.prod.outlook.com ([fe80::416:ea1f:d17b:2811%6]) with mapi id 15.21.0360.008; Fri, 28 Aug 2026 04:16:43 +0000 Message-ID: <53fbd974-71ab-40f8-88b1-f34254494fe6@nvidia.com> Date: Fri, 28 Aug 2026 14:16:34 +1000 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2] mm/migrate_device: add class-based migration trace events To: Matthew Brost Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, Steven Rostedt , Masami Hiramatsu , Mathieu Desnoyers , Andrew Morton , David Hildenbrand , Zi Yan , Joshua Hahn , Rakie Kim , Byungchul Park , Gregory Price , Ying Huang , Alistair Popple References: <20260828040817.1504092-1-balbirs@nvidia.com> Content-Language: en-US From: Balbir Singh In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-ClientProxiedBy: MEWP282CA0195.AUSP282.PROD.OUTLOOK.COM (2603:10c6:220:1d6::6) To CY1PR12MB9651.namprd12.prod.outlook.com (2603:10b6:930:104::8) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: CH1PR12MB9670:EE_|CY5PR12MB6057:EE_ X-MS-Office365-Filtering-Correlation-Id: b2838088-6a62-4b6c-d584-08df04bb2a5a X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|10070799003|7416014|376014|23010399003|1800799024|366016|6133799003|10067099003|4143699003|11063799006|56012099006|18002099003|22082099003; X-Microsoft-Antispam-Message-Info: 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 X-Forefront-Antispam-Report: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:CH1PR12MB9670.namprd12.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230040)(10070799003)(7416014)(376014)(23010399003)(1800799024)(366016)(6133799003)(10067099003)(4143699003)(11063799006)(56012099006)(18002099003)(22082099003);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 2 X-MS-Exchange-AntiSpam-MessageData-0: =?utf-8?B?U1EyM2h3dDIwVklLaG9SVGZEdjh4ZVprSHRBaWtYRVppOTN2TVZzcjZBYUFr?= =?utf-8?B?SzNrSUtldUVUU2NVSU5neDA1RVMyU2dMUnk4Mk50Y0ZDTXJBQWhlL0JIcTR1?= =?utf-8?B?NEo3L1JtN0gzTTFDSXdkbitPR0ExcEd5eUhEcXo1bU5RUCtYMGpJYlhyKy94?= =?utf-8?B?Unhha3NOT0ZmeEtoL3NtK2VIVnV4SWpCY2hMUUpmdVhiaUNrbXVLR2FXWDY4?= =?utf-8?B?QjQvckR3WUE0MGNWSEUwZzN0NGhxYmNObE1UdXY0VzdTeU93bW80ekNNcUhS?= =?utf-8?B?cjNidjJybktNMlZ2dHp1NkRtaDZRclVJaUJqNGcrNHZjdHAwY2o4SzdHOFNH?= =?utf-8?B?OHdScndIS3UyUG1qb0s4YzVDRGp0a2tRNkRqbnZwK29LQnpIRXB4Z2xGM3lJ?= =?utf-8?B?eEFHb0tGRlhpZVpQdFd0b0xnb25Ib3RhVHJ1U0tBekMzaWdtY3lrdjRKdVJB?= =?utf-8?B?V050cDFwb0pQQlZJNXFwdVFwQklEeUEvU2hYZ1ZQVW05Z0ZYcjhJREdUbHVs?= =?utf-8?B?ZElUdU9WaHJTODdnQk5GSEErWnZDL0s2QzR4RVJSY1NWWlZXUjhtRkJiM0JZ?= =?utf-8?B?K0xPV0p6NmhVYWJsaUpUbFNYMlFib2tNeE93TmhyMm1zdnFhUHRQTFd3MXpU?= =?utf-8?B?YVdxQ05uSk02OWF4SjR3Znh6aGZVMVM1cDNpN2FBUitVSVo5d205WEFCcmM3?= =?utf-8?B?QnN0RzlrL044Q1hkOHZYZ01ya1NCa09kbzRmT1pjQU1kaW5ZMi9FdnpCaDh1?= =?utf-8?B?ZUhQQS9iOUVYVnFaWWtNSWxCNUZzV0FFUGR1eVk4V2ZPNzNiRzQ2dmNFdkFh?= =?utf-8?B?YlRsbks2ZzBKTmVUVUcwUkJhdWEzV0hmMjI5TG9oSkQ2UFBUOVpOd3hxUUEr?= =?utf-8?B?VzdRUXdQNWpzWEtNRDJNUjRZZzMrVkJNMUlWRnNVSXJaUjlxbEJSVkZFMm9n?= =?utf-8?B?SEZ6QUU0cXVMU2pmUHZvZDlCSUwxVEdPOEZOTHJ3cGtQUERJQVBjeU9oTGVh?= =?utf-8?B?RDBra2JiZ2Q4dWdIQjIzbnZmRG1wRnNUUVhzUFlyOEFVYzR6cVFtRE92clNM?= =?utf-8?B?Y2p5WC9OV0FhSHZtUVk2dkhVN1FkYkVDVUlDM2RqMVowcytzenZ4bm1JZVFD?= =?utf-8?B?c2hFVzhZbU1iYU1YOXkvQk54cTBsaElmaUgxZFNKcFoyNTdNSUdQL2t5N3Az?= =?utf-8?B?Tzl4b0I3UjdodC8ya2hieTlsZTdUdTlDMC9VU0hPSDBteHVnVGxwdW12N3Vm?= =?utf-8?B?c1RTZnBORlZiaFQzbDRhVEQ1cjROanluVGx3S1VPNXRPNmF0eERIWFhjNFli?= =?utf-8?B?ZGl6RFI0OXlpUU9KelB1eWZQOG96anNramhleU9senFTNzg5bmNVd0lTQ1cw?= =?utf-8?B?WWxyOTJFaHNaeERhZW9oVFBpQ3BzLzc2MTJ5d0lBVWo2bm5xUUtlRERyMndK?= =?utf-8?B?c205OVZ3NzR3eTkvTXRMWkJxMHluUHpvdUNybXhkUjZPMkM2TUdvTFVabFZP?= =?utf-8?B?Y0xwZ0tLZjhiYmlMVUdPRnMwVVRnYWN3enlxQ21LL1M0K2lpUFJFeXI1K3k3?= =?utf-8?B?ZEZwdU4rT3QyMjA0THUrcVcyYmxiY1BxVnNwY1FxbmRFSFFKVEp6YWdqcjQ5?= =?utf-8?B?bnJ0UUNuWW5SamJkaTZuNzBWYlMrKzd1ZXJPcTZKckVHY1UxMzBLREdqTzYv?= =?utf-8?B?dGhNaWk1NjkvWUVXMFZUVzNxR255aTkwbWtrdDEyZGRNOEQyZDByZnVqNjdN?= =?utf-8?B?NC9xdjFVM3RJQTZmWUtkTDdhVzg2OElJZG84LzRNNGQ5cGRvZktySFVBelJW?= =?utf-8?B?cUhWSHY2Y0hFa0dLSFhyOWIrQktDZ0xRd1VqV0tLamQwalZQOFdxRVFaMlBK?= =?utf-8?B?UEdCTzBTa2owdERycjJZT1doUUd3VDdHbEpUV3dLQzlTRHVpd2pSbzlBYzEz?= =?utf-8?B?V0lYNXozWGJjMURPajA1ZU5VbWd0UGJIdkZZTy9ZUkRNbTZ6aGVaWFp4VmdU?= =?utf-8?B?K256STlNc0llSU1WT3N1STI3Vm9MdVU2QURYZlQ2RlBVdFNSZ3R3SjcrcnBZ?= =?utf-8?B?OVJFbHRFTlh5ekYvWUROQ29ZT3F4U3lMZWJaNzI3cG9IN2lQbzdOM1VtR3lL?= =?utf-8?B?Q1lMVVdBa0ZyTWhuck84NjRwSlZ3MTJhL3FwenB0bDFnWUdONzZDMXBDcnBl?= =?utf-8?B?U1ZOblBTMDlvRlhBR0hxVHdTU1QvbHFLV1JEamNKN1A3YjBIajgwOG1QRzJ6?= =?utf-8?B?TDJ3aHVGazZWTTI1dVlQWm9TK21uRzhhL0N3WGpoc0l5NW1KWGxnTnFJRGR4?= =?utf-8?B?ZXI0QjNhZTRRY1F2NTBUZmZSK3pQU2cyZ01LZG1SbUdkWjBWYU5mUkNJamxJ?= =?utf-8?Q?hNBUh2+KvcouV5ly2N48rXwXcaJGsNeHy1VHiJ4JHx+en?= X-MS-Exchange-AntiSpam-MessageData-1: Jm88rHXcTYZXxw== X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-Network-Message-Id: b2838088-6a62-4b6c-d584-08df04bb2a5a X-MS-Exchange-CrossTenant-AuthSource: CY1PR12MB9651.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 28 Aug 2026 04:16:43.7575 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 43083d15-7273-40c1-b7db-39efd9ccc17a X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: 5FVzB/Y69v0RDSfXUxTv9FbDlGLVgoCDyca9UZGA79hguQfLiD5cnNejJtOA7j8yPSP0HuAHsRX5bNLc2lI+4Q== X-MS-Exchange-Transport-CrossTenantHeadersStamped: CY5PR12MB6057 On 8/28/26 2:13 PM, Matthew Brost wrote: > On Fri, Aug 28, 2026 at 02:08:17PM +1000, Balbir Singh wrote: >> Device-private migrations currently require ad-hoc instrumentation to >> understand selection, unmap, copy, and finalization behavior. >> >> Add reusable ftrace event classes for migrate_vma ranges, device >> batches, and individual folios. Emit start, done traces with >> ranges, flags, page counts, success/failure summaries, PFNs, >> and migrate flags. >> >> Enabling all traces can make the migration traces verbose, when used >> they can also help debug issues with device migration. >> >> Signed-off-by: Balbir Singh >> Suggested-by: Steven Rostedt > > This seems like a pretty good adding tracepoints - anytime I've had to > debug issues in migrate_device.c it has basically start adding printks to > figure out what is going on. Hopefully witth the right tracepoints, this > would now be turn on ftrace. > > So +1 on the idea. > > In the middle of a few other things, but will circle back with an in > depth look at individual tracepoints added here when a bit more time. Thanks, I am hoping to add more tests and use these for debugging corner cases and hopefully get easier debug for issues reported. Balbir