From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from YT5PR01CU002.outbound.protection.outlook.com (mail-canadacentralazon11021110.outbound.protection.outlook.com [40.107.192.110]) (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 6388B1B3934 for ; Mon, 10 Mar 2025 15:50:26 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=fail smtp.client-ip=40.107.192.110 ARC-Seal:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741621832; cv=fail; b=pBMk8/GZQGDIPdddNwjtFPOsTbXKMY90Cbon39m0gnO+NLHiV3qt1ruz+PKZ6vy8oZAx4ZKrng3umZ158APeVF5bNG3PUTBCE5/iY+PYDbe7f8RAuDxctU6ULDNqSeUPilhhwMjmcWRkgfaVq56yXJR0ExJMpLj2+r1vhyvQK9k= ARC-Message-Signature:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741621832; c=relaxed/simple; bh=BNUV2mS6eUgJ3rGyn8taxIdmRUaIXTUb1V0Kj1jQ37A=; h=Message-ID:Date:Subject:To:Cc:References:From:In-Reply-To: Content-Type:MIME-Version; b=WXdc70T4ENGvK7qtQ2VDh6w8H+/enlaLTlC1+JUeYNZ+bvq2V99zBbc3LLtQdLzja54boa+ubGRQC4CEeXXavL5gimqj+HjMCKrvIWVk6Ukgaa9/M4Qn6qcwwXJxkItaqvi+BnCJhyhp6rJuH21CDRlBhdH70UbniqKMQaOOtfU= ARC-Authentication-Results:i=2; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=efficios.com; spf=pass smtp.mailfrom=efficios.com; dkim=pass (2048-bit key) header.d=efficios.com header.i=@efficios.com header.b=jc0Jcr0P; arc=fail smtp.client-ip=40.107.192.110 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=efficios.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=efficios.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=efficios.com header.i=@efficios.com header.b="jc0Jcr0P" ARC-Seal: i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none; b=mmDkbAJq7TluAu8jBAZvWHrGFsgZ0wSI9X0IeatizetTDgZTE1+UFvJAgjzXcSvwnNRwgDdfgeIHwJqkMMKG1jHsYiws4ocaKLA9gCFfkQ5t5B39ZDZQlUCFdGzfGNtpWZoqVmYIrJepM2YIJNqjacCPRtXxS9S4y0Ik4/Dl314jFwHOcWeFDxV00i36BuGAB4I45Iyzh3VX8wrmkxPmbyQRmEIz+JIkCZdT2OtKBfOpxq5vuDOvbIfQ3/c+y53v94UEzgQ5KFydwsE1+Si7fAc4uXIlEe7LBywQpfzG4ZcfaZnnU4ZaXyW7/9RRphbN6s93ZX9CRou4bGheo88pfQ== 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=yecAxySxOFswYBGnQ7/NvUNugZ9cvm5Xvj9fSooe/9A=; b=k8DXadeO7HmvPvm3yt5jJQgMcdKQ+THUUYEhRHOEAif7cduQGz8xA3IKifqq9IQdHVueIQ9bYZER93dSpDCHxLOOl74TjXWz8cLvJPJcXPSC4w9x+dF6o4WHstDp7UauVcQ3WaqNrTLGKFxKj7Ml/93DRl8ZDvUJMj0MKEQ77oBjZHS/Q2a1rbL+zidNgT4yqAt5wjF82nPz3gnzbhq8m0V3jgmxEAuO4hoFHGNllPZgchyEaxVAPAU80XGPR1oKl/AMuXITcT8gEoFkEJJYqWMwNtOKVItrtq1tYkGRjb9++wwatw99LY1hGvSUEazUDFUfF/5wTr36ylkDFrOBlw== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=efficios.com; dmarc=pass action=none header.from=efficios.com; dkim=pass header.d=efficios.com; arc=none DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=efficios.com; s=selector1; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=yecAxySxOFswYBGnQ7/NvUNugZ9cvm5Xvj9fSooe/9A=; b=jc0Jcr0PKA3ncW1zxiBl37naQxyYK+gs6SYK4SrIcuBrGalA+e4FmXdTttMC+C8VcR9C4g19VN+sP++N3R6f+VXpNMVqFrTwXXW/l01Wm3U2oPSqG33d93jOMvYGMb2JlYhbhegjI7iO3X+b6SBokEZHdK0N2cxYt3DBdk4CwKBrnOOfOxFhMyuRf7klpNHyIU2ch5NhVulyhm8gKh7MVYeO7lLDD6YT+OCTKwG/s2l68M9jQ8gX0SF3RplVHgLbF/t/kRXfPj8a6DusrHa5cXeUf5qZ9koEYfG4Whf701w8o+sPbWQZin/vxETClMJgt3+mciw2+wVe4aR7vneSfg== Authentication-Results: dkim=none (message not signed) header.d=none;dmarc=none action=none header.from=efficios.com; Received: from YT3PR01MB9171.CANPRD01.PROD.OUTLOOK.COM (2603:10b6:b01:a0::18) by YT3PR01MB9978.CANPRD01.PROD.OUTLOOK.COM (2603:10b6:b01:8e::5) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.8511.27; Mon, 10 Mar 2025 15:50:25 +0000 Received: from YT3PR01MB9171.CANPRD01.PROD.OUTLOOK.COM ([fe80::5393:fe91:357f:3ccf]) by YT3PR01MB9171.CANPRD01.PROD.OUTLOOK.COM ([fe80::5393:fe91:357f:3ccf%6]) with mapi id 15.20.8511.026; Mon, 10 Mar 2025 15:50:24 +0000 Message-ID: <31fa089d-1f55-4bc7-9323-389fda4cadfa@efficios.com> Date: Mon, 10 Mar 2025 11:50:23 -0400 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v11 2/3] sched: Move task_mm_cid_work to mm work_struct To: Gabriele Monaco Cc: Ingo Molnar , Shuah Khan , linux-kernel@vger.kernel.org, Andrew Morton , Ingo Molnar , Peter Zijlstra , "Paul E. McKenney" , linux-mm@kvack.org References: <20250227153329.672079-1-gmonaco@redhat.com> <20250227153329.672079-3-gmonaco@redhat.com> <1c161066bcbc916ae9d97e7d1753ee12511da085.camel@redhat.com> From: Mathieu Desnoyers Content-Language: en-US In-Reply-To: <1c161066bcbc916ae9d97e7d1753ee12511da085.camel@redhat.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-ClientProxiedBy: YQBP288CA0040.CANP288.PROD.OUTLOOK.COM (2603:10b6:c01:9d::24) To YT3PR01MB9171.CANPRD01.PROD.OUTLOOK.COM (2603:10b6:b01:a0::18) 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: YT3PR01MB9171:EE_|YT3PR01MB9978:EE_ X-MS-Office365-Filtering-Correlation-Id: 112b7110-1cd3-4ed2-8f2a-08dd5feb45ae X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|376014|366016|1800799024|7053199007; X-Microsoft-Antispam-Message-Info: =?utf-8?B?aGZSSCtKUzJzYWZHNVhYa1BpaXExZklLeWRBZDUycUxDZE84VW5oVVVzN0Ir?= =?utf-8?B?OWwvejcvMldKRzgzdTJ0K29qcnluVDUyVEpKSk82YzZMdk5CSXh1dDhYSnZM?= =?utf-8?B?aW1hM0ZnS0o3R211R3gwdEltVzErcnNyL0pZZ2NUZmR4THVlUklPWVEzRWRz?= =?utf-8?B?NmJXTURhOTY2TFdPbVlMamwrQzJpV1B6WmpqWEtNdDFWYkdDcFZyL0M5K1pC?= =?utf-8?B?MWY1em9LdHFZYndRRy94T2REdGwyUG94M05LLzNZWHlMY2tsK1RzbUVvWk52?= =?utf-8?B?UnluTXVIMXRTNW52UElLbXhMYlFHZW9WNldoM0FnV25nZkFjZEZQL25uempt?= =?utf-8?B?MG1ONjJGNTJwMmgyTXh2L0pFR0NpOExqRVVzV2gzbm9Gc0NsRU1MbHNJNTVx?= =?utf-8?B?NExzc0puK1U4RTc4UFd6RkxOOWExRzA2SWI2RmExK0tObU1uKzFVc2FneVcy?= =?utf-8?B?YUVWWGpXWXhOYmpzWEZ1YnpDTXZWYnBTdEZFSGFHbVQ5cHNtZ2tsbTZGOVN4?= =?utf-8?B?eFB0MVJ4ZGtmRlhPb0dMYnNZVGt1dVd0UUl4MW83VmZxeFhCKzNjRityRitX?= =?utf-8?B?YnVUeXRBNFhBSk9paWhiQkZMY1U1Nk9udlVaUkRnMW1rM09LTkFsLzlFcVlq?= =?utf-8?B?Q2piWDNCNU9wajlRVUZnbEthMzhjWDRsaFJVVUtBczBzcDVwUTN3RVI4anR2?= =?utf-8?B?eE9rS3dQZENVQld2WGdSbS9QRFhqSWJUZmc4aVJ3dlg4bjVTalJPeE1ubmd3?= =?utf-8?B?R0NERTc3TmdEOCtJY3RyN3NHTmM3ZUJKalVvMmpIZEpGZWR5L2pwL2RUMVQr?= =?utf-8?B?dkhvUGtESDBlM2d2Q3hQMFdrc3Z2UHhPeEhQSzAwNWRCOG10SUlueEhMcjRB?= =?utf-8?B?a1J6TzIzUXh3UTZFVGp2ZkNDYm9abmZMbUZuTUVZb09iNUxzbHJVaGRxWUpM?= =?utf-8?B?VVV0SEpmV2RhOVg5REptY3k0SXBJMVdVRy85cjk2bzJCWXdTWTFNbVlZdE00?= =?utf-8?B?M2QvYXk1TDJhYk1qUkMwWFJMcGlNdHE3MWtmT0Mxb0x1YXppQkZFTUE0eHZZ?= =?utf-8?B?b2RZRkUvazlTSnFNQys1UFAwblVRRmhTQVdkckJVZEhNR2M0WmUzU0F2RGpR?= =?utf-8?B?cC8rNythcjZoVjdTMDhsejVzQnFTVUpmMVkvcDlCZ2RzT3RFb05CY3AyZm1u?= =?utf-8?B?dkVuUDBkWVVXUzRsNWc0MVhjNE1FRmlwK292Z1B0RlFJd3VzaXJmbTI1disy?= =?utf-8?B?NVdPU2JRbWFEU3YzUlJ6K0ZHVGIyL2hiaUJsbXFNbUt6QUtQMHQ0SXRQZFpP?= =?utf-8?B?TmkxR044dHVmZnNZVU5qWmJRVGRKdFcwNEdrUjZCYVJnS3ExVTI2aWRwak1B?= =?utf-8?B?aHhZbEJqblZ5bUhNSTcwaEtWZVJJeHhTdkZNRnFXbVYyek02eVRvR1BFWTk1?= =?utf-8?B?Z3ovck1KR0QrR0svS1FEK0c5cnM5RDhlN1A4WlFNOXN5Uk82bm5XSitUd3BM?= =?utf-8?B?ZE83SjgySFcvUGxZOVBueE9uaEZmbHlicmkvSVFEQ0lNVkxQYmx3b1pOT1RF?= =?utf-8?B?SjlkMFFLQkt3M04yeWZQYVNCTUJKTkR4RlNFMjhvSE1HWjIzOHo3NFl4SVJT?= =?utf-8?B?anM4Nmp6Z2tCZUpFY1NSRWtybzRyNzQ5K2pUQUxKU1diWnc4aUhJVzRGTldq?= =?utf-8?B?ZUJNRlZDd0trMEpla01yOCtQMkUwd2YyTTZwV28zdG95c1d6YUY4TzV6V3Zm?= =?utf-8?Q?NMXwJdk6NloOaln6Kx5GpvpeACISS6X8eev24t9?= X-Forefront-Antispam-Report: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:YT3PR01MB9171.CANPRD01.PROD.OUTLOOK.COM;PTR:;CAT:NONE;SFS:(13230040)(376014)(366016)(1800799024)(7053199007);DIR:OUT;SFP:1102; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?utf-8?B?V25SVlkrK0RuZDFEN3V5WkluSXZxL0JOQXpVcVpGUVFDNWR6Sk9UczZTa3or?= =?utf-8?B?MWNoWGEzbmRLMENQcW10RHJtMUo0NWdLcytlV2w5ZVorMnZkYk9HRWphWHZi?= =?utf-8?B?MDFPcXJjRWZSRkJpcFZBUVRQNktDNE55KzJ1MXdNemt1WkRxQmlreldBWEcr?= =?utf-8?B?WTh5UGZCazZRVFI5VkJQbFJXWk9xakxEMTNyWjFjT3FNZXFYTW9idHhyc3BS?= =?utf-8?B?OHozdW9RK2lKczJ0OE4zd3ZEeXVmdnVoVnZTNnB2M0pIdTFVVkNwQklrd2V1?= =?utf-8?B?N2I0N0J0OHZPS1NxU2JZeGNWSU9pZml2UXRzbjdQTUU3NlptSStXdTVOdkNF?= =?utf-8?B?bkZWQjBjUHhOd1g0Y1B4N3dFc05WdVRkaU5JVjNqMDlSeXUvZjRkUktGalFY?= =?utf-8?B?WWUzZDFOZmVGY2VWdk9WSTlkRm5aSHRhQ2NvcWE4ZDRVMmpobk5FWDcyK0d2?= =?utf-8?B?cjVWVkhFL2Z2dXN5WVZkbHRsOGpObUtCT1V1aCs2T2hMSzlNSnFZSHhxeUhC?= =?utf-8?B?VUJCalNCalVrUXZaS3gvT21uaU1QWnVYQUM5N0ZwVXdWQmMyM1NPK2JhelpJ?= =?utf-8?B?S0tneHBqT2k0RmpTaUlKQmRXNU1ROThTK1RNeGZ0K1VlU2MxZVR3cEVSZVR4?= =?utf-8?B?blIvekZlcEJxaDhDNTFDMm8xNktCWGYxQWNVWmNMSnpCcVk1bXBIVG91eEdZ?= =?utf-8?B?SU9aa0IxTGczQkVPUFBpVFlwU2JCZGFERjBsaFJzcUFmdmIyZFoyMlo1NjBm?= =?utf-8?B?MVVNWTdPRXMxUjYyQmRvMzRJNnZTSEdLZzZ6Nndhd2tlclh3M0RpcnZrYmpw?= =?utf-8?B?c0dSeVF3Z1NQK2JVdmk2aEJzYXVDWmZEc1lhMFd3Zjd3SFpXRUJNNkhIZFIw?= =?utf-8?B?Nm1kbkhtN0ZkakRlZGVuNWpqeExoQ25reWFMelFJYWJ4MWEvRDhZQ3VLdnpQ?= =?utf-8?B?RnJxb3ZxVHFKRmpDVjhoaGpwcEhiaTFwWFJ2T0VjT0tLWFFOYStoYkJVdkw5?= =?utf-8?B?Q3pPL20vRlFTcjFRbjA1clhOY0N5ODRKL2hURDVxZ1FONGVtRDZtR1EwdExu?= =?utf-8?B?TVQzUHJPRjBYSnFTandITDFsbE9mbTNjcGp4cW52aGh4L3lFS0pKVjc1ZVBx?= =?utf-8?B?ZlRXeUZ0ald4WU05QURnQTRGb0YwRUg2bDhEUmExdmJvelJpTndLRWJidEcv?= =?utf-8?B?dGtMUDRqTTkyWXBoVWRIRFB1eklMS05UTUR2ejZDNmdpQ2g4KzlucWNjbmpa?= =?utf-8?B?WUM5R3hMSXNkRERncXA2UVFIT1NSZVM5MlE2U0pBY1Bja2NQYW9HNWVEdEpL?= =?utf-8?B?ZGIwcTRxOGhSQWVRZGRWSmVrTHloOFNyNlpmVEQ5SDJmV25Yem1oVmNuRWNk?= =?utf-8?B?M0laUzNUc1RkL2YrekRTNno4UWRHUzR5aE9qQkpMMEc5a21oOFpIZ2YyQ1Rr?= =?utf-8?B?bVRYOHJFZHIva0tJaDJvdy9Sb2Y1N3ByRnNEZGRpcTFKZHlWN0RNcnVPVmNJ?= =?utf-8?B?enJjM3VqSituek55eTByK2RUTGw2ek5nMU9Ka1IydHhoN2JPL2hpZStTRnE4?= =?utf-8?B?QVJzWHNaU0VDMUR6b1RoVUUvYnNsRVdYemd1bC8yWUxwdlI2OHp4alVsaFVB?= =?utf-8?B?TGJMbGZhcWd5cEVNdkdFWTZCVkJUaVY1TmY4VjRkWWJVVGdrZTd2akU2ZmJE?= =?utf-8?B?Nmt3ZCtudWNvMGNTZUJiRFRnMEQ0WWxrUHBQNlU0MHBXTkxIYy90ZjZvWGRC?= =?utf-8?B?cDRGbEsyTGI0dGtIR0FPcXUxU29DOUs0bXNZQS9KbHIrSUpuTnA1WG40Rmp4?= =?utf-8?B?aXZNSzRLWlVoODA1NWZQVWpaZy9lTEcycStPYkVCOFVlN3pCZW15RFZ2b2Uw?= =?utf-8?B?YkFTcUpnU2drdThxeklZQWFyVXBNVkVzOVJqMUlNdWhOU2RsME9JbHpZQy80?= =?utf-8?B?dGNaTmtOTDBZeXFrVk8xK3NHajVtWk5Zc3dpei9pRDFrL2FuYVQxSnlkWlpq?= =?utf-8?B?RGs5V09FYnh2Vi9ySDNEdEg0d3pWck5jM1dEU0YwUHUreGlaVXN6OEZLZnp5?= =?utf-8?B?YXduR0dyeWFtNTBUK2RYb2lOQXYyajF0czJZZW9DeDNXNDV1bnlObDIyTzRa?= =?utf-8?B?cEh0eUtzN0w0bFl6VXZnT2FCeFcwbWNLcmhBR1FjMHNoYmVNY2xQMDFneHJL?= =?utf-8?Q?6TKe3E+raeWOYNUDJFD8oAE=3D?= X-OriginatorOrg: efficios.com X-MS-Exchange-CrossTenant-Network-Message-Id: 112b7110-1cd3-4ed2-8f2a-08dd5feb45ae X-MS-Exchange-CrossTenant-AuthSource: YT3PR01MB9171.CANPRD01.PROD.OUTLOOK.COM X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 10 Mar 2025 15:50:24.8936 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 4f278736-4ab6-415c-957e-1f55336bd31e X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: QICBlkH+PqCF4WDfjppbQzGzAYgptRaz0qSjOAp3M94AH0/cv7GpF85aZ+4rnYswNRYWcMRn02pIuEYvtYbblUuKZXSszN6da81I5xeNcFY= X-MS-Exchange-Transport-CrossTenantHeadersStamped: YT3PR01MB9978 On 2025-03-10 10:46, Gabriele Monaco wrote: > On Thu, 2025-02-27 at 16:33 +0100, Gabriele Monaco wrote: >> Currently, the task_mm_cid_work function is called in a task work >> triggered by a scheduler tick to frequently compact the mm_cids of >> each >> process. This can delay the execution of the corresponding thread for >> the entire duration of the function, negatively affecting the >> response >> in case of real time tasks. In practice, we observe task_mm_cid_work >> increasing the latency of 30-35us on a 128 cores system, this order >> of >> magnitude is meaningful under PREEMPT_RT. >> >> Run the task_mm_cid_work in a new work_struct connected to the >> mm_struct rather than in the task context before returning to >> userspace. >> >> This work_struct is initialised with the mm and disabled before >> freeing >> it. The queuing of the work happens while returning to userspace in >> __rseq_handle_notify_resume, maintaining the checks to avoid running >> more frequently than MM_CID_SCAN_DELAY. >> To make sure this happens predictably also on long running tasks, we >> trigger a call to __rseq_handle_notify_resume also from the scheduler >> tick if the runtime exceeded a 100ms threshold. >> [...] >> >> Fixes: 223baf9d17f2 ("sched: Fix performance regression introduced by >> mm_cid") >> Signed-off-by: Gabriele Monaco > > Is this patch missing anything? > > I refactored a bit to have it build in configurations without RSEQ > and/or MM_CID (which was failing v10) Found a small nit. Please fix and resend with my reviewed-by, and that version will be ready for inclusion. Thanks! Mathieu > > Thanks, > Gabriele > -- Mathieu Desnoyers EfficiOS Inc. https://www.efficios.com