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 79343CCF9FE for ; Mon, 3 Nov 2025 03:18:42 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 539A48E001A; Sun, 2 Nov 2025 22:18:41 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 4EABB8E0015; Sun, 2 Nov 2025 22:18:41 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 38ACA8E001A; Sun, 2 Nov 2025 22:18:41 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0011.hostedemail.com [216.40.44.11]) by kanga.kvack.org (Postfix) with ESMTP id 1E8E38E0015 for ; Sun, 2 Nov 2025 22:18:41 -0500 (EST) Received: from smtpin07.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay07.hostedemail.com (Postfix) with ESMTP id C215D160911 for ; Mon, 3 Nov 2025 03:18:40 +0000 (UTC) X-FDA: 84067838400.07.D396497 Received: from mx0a-00069f02.pphosted.com (mx0a-00069f02.pphosted.com [205.220.165.32]) by imf18.hostedemail.com (Postfix) with ESMTP id 46B971C0004 for ; Mon, 3 Nov 2025 03:18:37 +0000 (UTC) Authentication-Results: imf18.hostedemail.com; dkim=pass header.d=oracle.com header.s=corp-2025-04-25 header.b=XPXWEIib; dkim=pass header.d=oracle.onmicrosoft.com header.s=selector2-oracle-onmicrosoft-com header.b=Pxnz0lN6; spf=pass (imf18.hostedemail.com: domain of harry.yoo@oracle.com designates 205.220.165.32 as permitted sender) smtp.mailfrom=harry.yoo@oracle.com; dmarc=pass (policy=reject) header.from=oracle.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=1762139917; 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: in-reply-to:in-reply-to:references:references:dkim-signature; bh=DRWdXbzAfA2tGfUUDC2BaxyIXl+NK1Brz1xL/g3lIkc=; b=jM60dFZxWQiDVPOePQJrxphSHH4FUS07qroO5yLpGKR7pD2vosGCjhiofsyz4yKbL0RC6z C6PT2JHEi/et5QyZqIqiRZUFw8GBOxPvCNJQzmql9XkJxZ5JdzT+LtVMCbleWjGju6/M8v 1xEVvvRg0oVb1bPd6oymwSmmD7RYBDc= ARC-Authentication-Results: i=2; imf18.hostedemail.com; dkim=pass header.d=oracle.com header.s=corp-2025-04-25 header.b=XPXWEIib; dkim=pass header.d=oracle.onmicrosoft.com header.s=selector2-oracle-onmicrosoft-com header.b=Pxnz0lN6; spf=pass (imf18.hostedemail.com: domain of harry.yoo@oracle.com designates 205.220.165.32 as permitted sender) smtp.mailfrom=harry.yoo@oracle.com; dmarc=pass (policy=reject) header.from=oracle.com; arc=pass ("microsoft.com:s=arcselector10001:i=1") ARC-Seal: i=2; s=arc-20220608; d=hostedemail.com; t=1762139917; a=rsa-sha256; cv=pass; b=OCos3JCIsaFwjAJc75az6PFNWTM7dNAI9sNmiEl/ZGWmvM8nm3vTmgXtziZbZOX2zqzsQN PPd5DVdsIOK5WlSLhOyhXGeRlNdlJDD5kjA5DWYTd1XhnxMtzpZwTad9StA5xdnzSppnOW rCgX5Tx+0TqpoPia+kqu9fGCYAYITuU= Received: from pps.filterd (m0246617.ppops.net [127.0.0.1]) by mx0b-00069f02.pphosted.com (8.18.1.2/8.18.1.2) with ESMTP id 5A33EGdd019903; Mon, 3 Nov 2025 03:18:28 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=cc :content-type:date:from:in-reply-to:message-id:mime-version :references:subject:to; s=corp-2025-04-25; bh=DRWdXbzAfA2tGfUUDC 2BaxyIXl+NK1Brz1xL/g3lIkc=; b=XPXWEIibekMohMCSxeU52JcB+zkGdu/kf1 z3BRfDnC5iZO52iw17QtS8ATuLRJyNBYTb5+JVjL3ZQZooU+hlnpQpLyohENWlwW tCsLp9xscITl8QkmpJEwxqYSII+8W0yi48cgKwVML81c7JDezyFSIckUhmkfGu0w 8MLxDfNkzNwptk5ALsXX7zhY0yltQ8fEXQFMi2KmlFKMwPixN1CyR0dOY1yudxS8 DFOZTgMzGrnmOZnbPIzlJhwduhSb1m7KCEP+2npogSTqzF/tSyiY9jv5OCN/1EI/ 7iZeWpqU35O0feao641x7NstoI2G865f9oZK2IAsMRQGR46Zuvrw== Received: from phxpaimrmta03.imrmtpd1.prodappphxaev1.oraclevcn.com (phxpaimrmta03.appoci.oracle.com [138.1.37.129]) by mx0b-00069f02.pphosted.com (PPS) with ESMTPS id 4a6mah806f-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Mon, 03 Nov 2025 03:18:27 +0000 (GMT) Received: from pps.filterd (phxpaimrmta03.imrmtpd1.prodappphxaev1.oraclevcn.com [127.0.0.1]) by phxpaimrmta03.imrmtpd1.prodappphxaev1.oraclevcn.com (8.18.1.2/8.18.1.2) with ESMTP id 5A30AJPU016019; Mon, 3 Nov 2025 03:18:27 GMT Received: from bl0pr03cu003.outbound.protection.outlook.com (mail-eastusazon11012043.outbound.protection.outlook.com [52.101.53.43]) by phxpaimrmta03.imrmtpd1.prodappphxaev1.oraclevcn.com (PPS) with ESMTPS id 4a58n7b03e-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Mon, 03 Nov 2025 03:18:26 +0000 ARC-Seal: i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none; b=vdQTfvq/aeWCJIz7xGHopuUbPNjpl2AWtikFkygoEudFHybNgnBod/RSQtnt3U61dGxpMs80QPPes88WDlcimO49LbZCEC0vCpiRH0oysZwgTqJUW/t1jTcioZLLU4v2FxA3S+A1VT/yIe+6oicFGv2lTeCTeqp/99JEOy0H80WhmzuqyNh52GWO18lMVDhMk4E2ieodUGUf/VMZ6/kOCc9c0d+TtgiG1l2Q70sQ3fSrMTGziFPtvOqzgyCX/hb7ln8+DtyWSwBvPnDQzybcjNBpT6zP706G/yc2p5+x6IL3kieb6ItDYUJSp+R3PPfro163/ewH00gyoZVVFvYNHA== 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=DRWdXbzAfA2tGfUUDC2BaxyIXl+NK1Brz1xL/g3lIkc=; b=WAMbeX1biAZMbpXHqriN/xpYCjPfVhL59Lpkx0/ksF+FAKzUtgb3s9tgIR15/6ztCOvF/0mZWNvOTIycRZAKxEctbNJtKQMXnGoLCec1RynV2lG0wi+H2ANh1I07HoNHnyt//M55dl9oalwxnMl+uyoVB1eDTA8OI23heWF6mI+pPJKnZzSERE09362pAEEojwttcrzvAC6sqTrJuw4dixMTpJiqHpl33Nx0U2xpgDx8LdtZ1bW+OkxupAVx1u7ZyBapoKxRVvkASe0drsgwhbd5bId/5F5jctpNpd9NS6NqvTn6b/cPgC4/sbyZSZuGFrjeAxjKYzIJdDfZMBCypw== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=oracle.com; dmarc=pass action=none header.from=oracle.com; dkim=pass header.d=oracle.com; arc=none DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.onmicrosoft.com; s=selector2-oracle-onmicrosoft-com; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=DRWdXbzAfA2tGfUUDC2BaxyIXl+NK1Brz1xL/g3lIkc=; b=Pxnz0lN6k3ZCrX0w49niph9jdo9ntgIwvQH7tPcOuGMqXuSUtbif67Lm+yFS3garFwM2N4/90naF6GtK8pctGVyy4uPrVFBcwil1ucgr+NQZUMh5CecU1ML73rIoX34mx6PS89BpVuQAnvq5BzVwORzavefa3uEcp8+25jwaoDQ= Received: from CH3PR10MB7329.namprd10.prod.outlook.com (2603:10b6:610:12c::16) by CY8PR10MB6907.namprd10.prod.outlook.com (2603:10b6:930:86::8) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.9275.13; Mon, 3 Nov 2025 03:18:00 +0000 Received: from CH3PR10MB7329.namprd10.prod.outlook.com ([fe80::f238:6143:104c:da23]) by CH3PR10MB7329.namprd10.prod.outlook.com ([fe80::f238:6143:104c:da23%5]) with mapi id 15.20.9275.015; Mon, 3 Nov 2025 03:17:59 +0000 Date: Mon, 3 Nov 2025 12:17:46 +0900 From: Harry Yoo To: Daniel Gomez Cc: Vlastimil Babka , Suren Baghdasaryan , "Liam R. Howlett" , Christoph Lameter , David Rientjes , Roman Gushchin , Uladzislau Rezki , Sidhartha Kumar , linux-mm@kvack.org, linux-kernel@vger.kernel.org, rcu@vger.kernel.org, maple-tree@lists.infradead.org, linux-modules@vger.kernel.org, Luis Chamberlain , Petr Pavlu , Sami Tolvanen , Aaron Tomlin , Lucas De Marchi Subject: Re: [PATCH v8 04/23] slab: add sheaf support for batching kfree_rcu() operations Message-ID: References: <20250910-slub-percpu-caches-v8-0-ca3099d8352c@suse.cz> <20250910-slub-percpu-caches-v8-4-ca3099d8352c@suse.cz> <0406562e-2066-4cf8-9902-b2b0616dd742@kernel.org> Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <0406562e-2066-4cf8-9902-b2b0616dd742@kernel.org> X-ClientProxiedBy: SL2P216CA0194.KORP216.PROD.OUTLOOK.COM (2603:1096:101:1a::19) To CH3PR10MB7329.namprd10.prod.outlook.com (2603:10b6:610:12c::16) MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: CH3PR10MB7329:EE_|CY8PR10MB6907:EE_ X-MS-Office365-Filtering-Correlation-Id: bcc61d76-afc1-457e-6322-08de1a8796f3 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|7416014|376014|1800799024|10070799003|366016; X-Microsoft-Antispam-Message-Info: =?us-ascii?Q?Oz+gixBRSujsMaggMk/YjdAL2+9aiRgqS7lNgD4ZwqI3FMmVGjsH3up2i82x?= =?us-ascii?Q?LrXGbZuN4ye0Gyw7A0KIGjyz+4ZC+X1dHQsdTXiQLubtAncy9NPY0GxUMDxA?= =?us-ascii?Q?Q/EwS/wYBQBUZcUDM5GekvG4snpXyEXtxkrSRy2x9TTpJSpOg9uHGoIat3l6?= =?us-ascii?Q?jYsir+tiOyiWz5N2pFu46OjS8KS38WSNPN/Wqxxt3zu5bf5P5VfndfhPqXEw?= =?us-ascii?Q?4rgF3UWPoCNYL3M4OvrotpMX9ik0b2TQWuPxtEaS6MCetr3PXaewG7scVL7J?= =?us-ascii?Q?w0TJ4WasshYfazRK+HjG1e1qNvPghzKkEDUDr9fRCEtUP/q4sDdR4zP9wlLf?= =?us-ascii?Q?C8h9D/ONQwrHW9vkvf+i+P9cDHCtlTZKRqwHnqmVsT3mKHxC01DmlPTat9hl?= =?us-ascii?Q?92gQXh5I5ZSxbqU02J19JwdfBJ3cTx7APgQzyNEZ3Ocm9m25BYytPxrpZy2Q?= =?us-ascii?Q?h2fehQzXPYk3Yhn7yvSDTieblPO7g/mCPbV/cshHNy0sM0MrEP+07hBLsZHv?= =?us-ascii?Q?MQpqLYRp4Ei9klRGF9c+0bg/rhLqIqk8vtY71WL63WegYPEzT7ZX7kxyskry?= =?us-ascii?Q?vjc/1DwEuz7IZCz6Wuw54wuio3N1UpflgXyT2DYeWs9/Sy9dFQFraUYZhNj3?= =?us-ascii?Q?DvGFvoHJZR4Ue7Ec3VM+0ZufhNUydJeF5rSloZdDkDI972/DpciUET5J9ksu?= =?us-ascii?Q?4np2/PKBVdYpQfSOyXnR/iCwBkVKaXrDTWlOaOhBBqnHY7guwHnfXiQs/8qu?= =?us-ascii?Q?5qefxyOLgAUdW+U2dYvUN2eYQxUJ0zis9vTgxs3kAVMOV7vjNg9mpbUy90Fb?= =?us-ascii?Q?zRo0UA9H/qavkxTVyIniakJbPl4D9ZSmM46nBOt/u4E3yz3zW88M1WO3tF53?= =?us-ascii?Q?fsu/QElqNOfxft9uSR4udF/c84mZdBc6Nc9yJpzj8rELElcksLYeg3lU0h6D?= =?us-ascii?Q?XmXO9t2gcpgI8LqcjkxRg5mgjqIDVjx4eh0v0VwFl+zCd9b4apLOSHc6saFN?= =?us-ascii?Q?AKV37j87SInUdorj8TybWcrvcXTJyRRkqTS9NfPgoLYsJBFYXLw3FLCrv4Da?= =?us-ascii?Q?oZjn394dSHv/7KGHeu9BkUVLi6VVZHr2VLAep+4PJVlLUzcWxgNO79vp/qyO?= =?us-ascii?Q?oSUkFHJMo3uJMXafD6SeSjGhbTI7AgVYcRa7pbOjJD5VbHYarD3moEObXkZE?= =?us-ascii?Q?zC5isqn/JKWq4quEyHKkoVzBUsBnxP1Fv1EDucebz1LHVMo/hFIiMWl/grBF?= =?us-ascii?Q?jfEbxJCmX6XDkIP6vMAtx2A9zXM54gQ46S6ieJ8K1MZKNUykeuxYbid+BAto?= =?us-ascii?Q?dVQ+TkFlWwT9bEu9+cFqr5GuHEN8AxzRc8tlidxIUzMZVCuKNcOqpNy/A7bE?= =?us-ascii?Q?hy8TIUp9T8CwUTQusreZfSGwqamlYzIoPTgENEVRhfesUofTv10XcneYwD/F?= =?us-ascii?Q?leuFkleegLS439j81RecCbpwQmvDmj2Y?= X-Forefront-Antispam-Report: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:CH3PR10MB7329.namprd10.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230040)(7416014)(376014)(1800799024)(10070799003)(366016);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?dgXvDwDjbUWFQd5+tysDTE4l/l9BNVmDdWS8ErKAPD0GEEWtEqZJ3je93dMs?= =?us-ascii?Q?QQES+DLlqHEW3odlJyq6N4nLbiYRGmgfTrhuduYT1evQyjZKZHxtYwbx0gWn?= =?us-ascii?Q?EdiYdISUeCICP/r1IHlRP4PZGXhrmdPwPIQujfXyUJtwFW1SKwVU1VYy3Zoz?= =?us-ascii?Q?SYqDxGBqwSUNjF7PCZ9QZj4p/3yQqKYYRdfJE5xyHvfFb3+rHui6sO/Y7SvY?= =?us-ascii?Q?Ycada7ICvpKt3M+SRUKOBj7dYLsDPgX5gu4pwkkjTMoOLmnegcDyvqrNPak7?= =?us-ascii?Q?nr6aufZFdYPlN/Aajxtk5ZQVJquwBxceoIooXtmKFGaOPgGArKp/Ot9owu1r?= =?us-ascii?Q?Njqp8HL/ieP5RHkeCZiGKUfNJ+zoMa8I/b0QMDqXFo+RGhcPXx2tg4FWpRFy?= =?us-ascii?Q?Duo03E+dCAfpUCDb/Nap2s9umqtPaCKWZ7fJl4S4cW53I1mSe8kfeLaIawCf?= =?us-ascii?Q?4L8irOU2Jj+mJA/G9Lg6yhzTA4wc+DqRxzU5ya79cBvQiFJqiYIFQctz6nI4?= =?us-ascii?Q?DwWvKv3jYtUIBBv4ylbS1o4uBSNmaeE96VvqR07W4dlxMgdwHwxrw4hgfOmG?= =?us-ascii?Q?UMkHeOk8A3kcsI+TFoEDR0rJttSnaobtX26J5AZMP+xpJ12jJcnVT+E81+B4?= =?us-ascii?Q?oYG+d3aH2D8bpMFraV6NBxJXldrg2AZ7tjjCsI/kYDL8CcMPPMV1qswkeFzT?= =?us-ascii?Q?Wz9ZGcSoxW0MzSogQSKcE5x73C4pccmyGCDCN83ms+0m1nja2qwZdHl9QgYY?= =?us-ascii?Q?LliZZdXPCH+76k4ysLTD4wTuuCsVO+d22q+YtyKPymjsJNEOla0KMGeY6r+4?= =?us-ascii?Q?866JOjdG/3gBlPFMVKubvPmhZ9V3OTL7chv3LGPvUKjMm0VK/L48QGCZLnbW?= =?us-ascii?Q?3idlehi+M3YPV2f78LgR5Nr3PiU4CVLnF3KZ0wLbUofmAcBnOQNogOzOp6mC?= =?us-ascii?Q?zgKhmk3xgTqiuXnHn3LxHyRLkGnf0XlsK8ICypzuRbD4jcm7hWN7vv8Ocsur?= =?us-ascii?Q?zXIvSiYRCp/xh7QARStsgZoron0Bt5AwUN26UJHJGxZqhNqomXQ+vsJ28Pc8?= =?us-ascii?Q?oge9GDTNqzhp7oKyhFnWKDcJ/1rXfUCAjyXp2ltUKGipnQugmcYmkBXiZQq6?= =?us-ascii?Q?sTOtZ8O27SDkVdkr6F5x6pbz8j16XqQDWr1dMiogDrFNYmCweaCpvDisGEI+?= =?us-ascii?Q?rl3SWCMVv0i3d3UyDLcHk4qSn4YxnBy2SKiBiFyknMf0iklDh6oAk/g94qw9?= =?us-ascii?Q?nsKlnxwBFpePMfla/UihiUZajSjrrvxjFZUExSvhIZc/Bz3mRMV4OgbTgsM+?= =?us-ascii?Q?gFCIM6f5tAUIuhHBis7qDOldmRCRqya08Qo5mS2v9o7cpRBRUSMRhd2ftJpr?= =?us-ascii?Q?a/ttaOcdU3Q4d+x1TYkydUtcNWchEg4ATkgnLFFqLxmoHSb/X3QHWeuIgAXi?= =?us-ascii?Q?3gNCoUNBCXwaEGcnozvppgz0WdjWpIck7A76dLquHiYeAFMGq2yyWl93eQfW?= =?us-ascii?Q?RIr6353NDLulRkmKcclASUGIFBbbofMexkRSD36LjS8zNT6L0fDEj5RxFGh8?= =?us-ascii?Q?/zlC5nO2nWQoNpsKL/F20Jw+REVU88dwpGZvMTX1cD4lCcwNT6/lggNCTzsI?= =?us-ascii?Q?JzSLsZBmGq9RcU/5SPPJUQaskw/KveCYgt06x9x7O9/b?= X-MS-Exchange-AntiSpam-ExternalHop-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-ExternalHop-MessageData-0: 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 X-OriginatorOrg: oracle.com X-MS-Exchange-CrossTenant-Network-Message-Id: bcc61d76-afc1-457e-6322-08de1a8796f3 X-MS-Exchange-CrossTenant-AuthSource: CH3PR10MB7329.namprd10.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 03 Nov 2025 03:17:59.3413 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 4e2c6054-71cb-48f1-bd6c-3a9705aca71b X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: A0r4UOk2GOSumH7JVTRTOTQuibFAKxCsw394yjjXuxOHNql48FTv7Z0JBKp1gXuDzeb4UIgxrzXsHvRk/374qw== X-MS-Exchange-Transport-CrossTenantHeadersStamped: CY8PR10MB6907 X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1121,Hydra:6.1.9,FMLib:17.12.100.49 definitions=2025-11-02_02,2025-10-29_03,2025-10-01_01 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 mlxscore=0 mlxlogscore=999 spamscore=0 adultscore=0 phishscore=0 malwarescore=0 bulkscore=0 suspectscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2510240000 definitions=main-2511030028 X-Authority-Analysis: v=2.4 cv=UJfQ3Sfy c=1 sm=1 tr=0 ts=69081f03 b=1 cx=c_pps a=WeWmnZmh0fydH62SvGsd2A==:117 a=WeWmnZmh0fydH62SvGsd2A==:17 a=6eWqkTHjU83fiwn7nKZWdM+Sl24=:19 a=z/mQ4Ysz8XfWz/Q5cLBRGdckG28=:19 a=lCpzRmAYbLLaTzLvsPZ7Mbvzbb8=:19 a=xqWC_Br6kY4A:10 a=kj9zAlcOel0A:10 a=6UeiqGixMTsA:10 a=GoEa3M9JfhUA:10 a=VkNPw1HP01LnGYTKEx00:22 a=auTrCeKoL-_gxoL8Z8sA:9 a=CjuIK1q_8ugA:10 X-Proofpoint-Spam-Details-Enc: AW1haW4tMjUxMTAzMDAyOCBTYWx0ZWRfX4aXkffui2sNA tp6ZrxEjAk1+txcO3KcMPsngmi9gFjoi0Y359UYhOrtPs9DQoahqkvT/ZcePcoyKwgoEkMopTdd oGwGlDGUWks6RP748Wi++rpK7KZs5aowwDhzpVGi1vpN9Y3D2tN0+2Pdr0UbEni3H/JKk5ssEq8 DLZZ14EA5GMxk7igKFf6N/5SHvIH4CQab0AHIQ6uQXzIpLNg91zwCUgd1Em5ukMfQWaijjNmpJL 5eko23U3fKTnRalXt3vIULpbqKx/6CsE80XDIXvckmFREDfiBrDZf2cFJ7ygusPuYGpCc7Lx4Sc KdMEzFdYS5Z87BxmwZCqI8iyycuEfOq0zArxMgwYcdw6jlBUFtQJYWU4TDtk2QjqA2AiwV6thuF B8JIFyWIeY/5BvXryHyV5IRz8geBaA== X-Proofpoint-ORIG-GUID: DbeBeOXKNV8aPmQl_4wPw6CCBvccSXJU X-Proofpoint-GUID: DbeBeOXKNV8aPmQl_4wPw6CCBvccSXJU X-Rspamd-Server: rspam10 X-Rspamd-Queue-Id: 46B971C0004 X-Stat-Signature: 8hcid3jbdirhaox3ao57jnc6b3mqi7yy X-Rspam-User: X-HE-Tag: 1762139917-805816 X-HE-Meta: U2FsdGVkX1/mfUyuT0smm3Z8JbK0syiclNff8A3tj+UCtI6pF9yWxHxI/Y25jwTpbH7t6Kjn8m2JBfnh/aXdM1ttN3U4Q7Mynar4l3xIDv6a8q/V7rdNHnAgp0AFzEBgGbIhSH2UbWU69mJAqy1/wUCAzZVvbCLyitXji06MMWHA2gM0e4nGF/tmXjxmsCzCZ+LTsxAG+en37LiWvZjn3m1/WqRGmgjtuWYz8gE+prgbb00j3xfQOxIhcO9VnFT4rGGZ79rcDVUymX4XWuwlukzc11M3Xbtv6yTfJcCPMx/zYyJ9/hmELyrFqq1YMBtu0tkSoax28rK3wXBkcX8RLV8zP9f6CT35V/yHC3SHRnNByvjIAgp/0KQ1SRg88Ym/jmbjVprPceHOccD8ce6C5iR/qKFSfcD49NtovtJWIKCQACuPUQVtNGPi1Ndqyje3f04D3n5NiA5GDKwf/eqPekr1wNhu+jTfrFRQrp3B3jClPGgLrnBwCa1krLXNMFxnclYFpYSBnEzm1du5gNKdDTugCPwPteO0WSGNINImptkNBSjkMkmiuuk2ewgN9lgM6OJcqLz+SeY393Sw1kNUxel35VImL43/r25CLHtpJqW4EvLqV85yVy2HJMpUO59btv+eCP6It3t4s6I47vOv7EApTp4fBlpwUIAvasS+l4CUXsFuBgWsp9x0uGERL/ZObyKNILDXqIrkWYvvYs3nuBSGd6cxTZ0V+nt74AUmWrqQ6RSwsVm/UIUKX03g2lofdz3ti/0q3qeEOy974LJf4UlMWnRT6vBceaEmvp7Kxk/amSY1SE0PX5CxZB4GdUmx6XUGMcWOLboGCuPILnwlqFmdzg7XNuzyQ7KFhm84QpV8A6tEbVKZEjO3dct/X82YMMWHwE6aTLzUjePcGw43rfVarfvfqliNabpgUlD0HFRklddNOXk9szcDdj5nz4nkye6fBOtef6FsUByhfYd xQIIw98Z 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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 Fri, Oct 31, 2025 at 10:32:54PM +0100, Daniel Gomez wrote: > > > On 10/09/2025 10.01, Vlastimil Babka wrote: > > Extend the sheaf infrastructure for more efficient kfree_rcu() handling. > > For caches with sheaves, on each cpu maintain a rcu_free sheaf in > > addition to main and spare sheaves. > > > > kfree_rcu() operations will try to put objects on this sheaf. Once full, > > the sheaf is detached and submitted to call_rcu() with a handler that > > will try to put it in the barn, or flush to slab pages using bulk free, > > when the barn is full. Then a new empty sheaf must be obtained to put > > more objects there. > > > > It's possible that no free sheaves are available to use for a new > > rcu_free sheaf, and the allocation in kfree_rcu() context can only use > > GFP_NOWAIT and thus may fail. In that case, fall back to the existing > > kfree_rcu() implementation. > > > > Expected advantages: > > - batching the kfree_rcu() operations, that could eventually replace the > > existing batching > > - sheaves can be reused for allocations via barn instead of being > > flushed to slabs, which is more efficient > > - this includes cases where only some cpus are allowed to process rcu > > callbacks (Android) > > > > Possible disadvantage: > > - objects might be waiting for more than their grace period (it is > > determined by the last object freed into the sheaf), increasing memory > > usage - but the existing batching does that too. > > > > Only implement this for CONFIG_KVFREE_RCU_BATCHED as the tiny > > implementation favors smaller memory footprint over performance. > > > > Also for now skip the usage of rcu sheaf for CONFIG_PREEMPT_RT as the > > contexts where kfree_rcu() is called might not be compatible with taking > > a barn spinlock or a GFP_NOWAIT allocation of a new sheaf taking a > > spinlock - the current kfree_rcu() implementation avoids doing that. > > > > Teach kvfree_rcu_barrier() to flush all rcu_free sheaves from all caches > > that have them. This is not a cheap operation, but the barrier usage is > > rare - currently kmem_cache_destroy() or on module unload. > > > > Add CONFIG_SLUB_STATS counters free_rcu_sheaf and free_rcu_sheaf_fail to > > count how many kfree_rcu() used the rcu_free sheaf successfully and how > > many had to fall back to the existing implementation. > > > > Signed-off-by: Vlastimil Babka > > Hi Vlastimil, > > This patch increases kmod selftest (stress module loader) runtime by about > ~50-60%, from ~200s to ~300s total execution time. My tested kernel has > CONFIG_KVFREE_RCU_BATCHED enabled. Any idea or suggestions on what might be > causing this, or how to address it? This is likely due to increased kvfree_rcu_barrier() during module unload. It currently iterates over all CPUs x slab caches (that enabled sheaves, there should be only a few now) pair to make sure rcu sheaf is flushed by the time kvfree_rcu_barrier() returns. Just being curious, do you have any serious workload that depends on the performance of module unload? -- Cheers, Harry / Hyeonggon