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 B0701C71148 for ; Fri, 13 Jun 2025 17:58:51 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 4A4436B007B; Fri, 13 Jun 2025 13:58:51 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 454CA6B0089; Fri, 13 Jun 2025 13:58:51 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 2F56A6B008A; Fri, 13 Jun 2025 13:58:51 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0014.hostedemail.com [216.40.44.14]) by kanga.kvack.org (Postfix) with ESMTP id 0BB776B007B for ; Fri, 13 Jun 2025 13:58:51 -0400 (EDT) Received: from smtpin10.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay04.hostedemail.com (Postfix) with ESMTP id 6DCA81A0EFF for ; Fri, 13 Jun 2025 17:58:50 +0000 (UTC) X-FDA: 83551138020.10.D9BF6E6 Received: from mx0a-00069f02.pphosted.com (mx0a-00069f02.pphosted.com [205.220.165.32]) by imf19.hostedemail.com (Postfix) with ESMTP id D16FC1A0005 for ; Fri, 13 Jun 2025 17:58:46 +0000 (UTC) Authentication-Results: imf19.hostedemail.com; dkim=pass header.d=oracle.com header.s=corp-2025-04-25 header.b="WxMol6/I"; dkim=pass header.d=oracle.onmicrosoft.com header.s=selector2-oracle-onmicrosoft-com header.b=ZDRvwzUI; arc=pass ("microsoft.com:s=arcselector10001:i=1"); spf=pass (imf19.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-Message-Signature: i=2; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1749837527; 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=SWd85zIAstAnrapTEfqyAMxGq34bG94sh3Z+CjxvV8Y=; b=GIB/kWf5e9DvYsFtqqI/U3Pcsi94m8eg9FbafS6ZWJzqJcY0gftqQ8Xht4DXbpPUYaSFqr K92eptAwjEnmKgJj6MDmfFFrNdiutME8ktDu6O1My+FsmZM/wlTRb+fEbg9G8Ry5wCHMz7 C944wuqhe8C0kpQyPJWfEjxdds9Yxcg= ARC-Seal: i=2; s=arc-20220608; d=hostedemail.com; t=1749837527; a=rsa-sha256; cv=pass; b=bdRdn3ArRi1reQp6m0uOw66mTDDkn70MkxVrmEYhoaYVr9p4OrMyvZbmELk+LUtrs9SEBb f3fwow0kRVfcGqmOB/bdRpRuHvPuOUcmR/oZQVTmMJ6nhKhYVa5jk/u6uME7eOxthMom1o dxX9X036LC/pNE42plhP4/9f9d2DRos= ARC-Authentication-Results: i=2; imf19.hostedemail.com; dkim=pass header.d=oracle.com header.s=corp-2025-04-25 header.b="WxMol6/I"; dkim=pass header.d=oracle.onmicrosoft.com header.s=selector2-oracle-onmicrosoft-com header.b=ZDRvwzUI; arc=pass ("microsoft.com:s=arcselector10001:i=1"); spf=pass (imf19.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 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 55DCtcSU007756; Fri, 13 Jun 2025 17:58:36 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=cc :content-transfer-encoding:content-type:date:from:in-reply-to :message-id:mime-version:references:subject:to; s= corp-2025-04-25; bh=SWd85zIAstAnrapTEfqyAMxGq34bG94sh3Z+CjxvV8Y=; b= WxMol6/IfuZ7boOQwcU/T37w2PLRKBfrWhPW7VZnxnJVI+wuWV9x4pdofHFdeAac C0YhV9cdvDFq4l6WtuPAw7Kp5ZEnz81mG2p8KcaDsGGBAJtmaHsAzx+mIMCcqPmH Fo1My/8sMtm5OjwRs6qMH6BL/KcY5gGwDq3Odldt3wLaMV4YES1J2uzdNJJnfgPS 6uL2BJiXDQJ+1jLL2eekz8eejCSKlmGCOCoAkrBcj/Tajk+DdlCAszxSICxMMvUS TfOSoJMrjCh9DeMaVYITRxvGGjOg5tYZl0/YYZYLxfLJZT/B9VZvzTeMWfzKabaD qTfc8gU7NFpln6m1mNqqrQ== Received: from iadpaimrmta01.imrmtpd1.prodappiadaev1.oraclevcn.com (iadpaimrmta01.appoci.oracle.com [130.35.100.223]) by mx0b-00069f02.pphosted.com (PPS) with ESMTPS id 474dyx458b-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Fri, 13 Jun 2025 17:58:36 +0000 (GMT) Received: from pps.filterd (iadpaimrmta01.imrmtpd1.prodappiadaev1.oraclevcn.com [127.0.0.1]) by iadpaimrmta01.imrmtpd1.prodappiadaev1.oraclevcn.com (8.18.1.2/8.18.1.2) with ESMTP id 55DFwdEr009184; Fri, 13 Jun 2025 17:58:35 GMT Received: from bn1pr04cu002.outbound.protection.outlook.com (mail-eastus2azon11010007.outbound.protection.outlook.com [52.101.56.7]) by iadpaimrmta01.imrmtpd1.prodappiadaev1.oraclevcn.com (PPS) with ESMTPS id 474bvdwejp-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Fri, 13 Jun 2025 17:58:35 +0000 ARC-Seal: i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none; b=JVbYOZi2v1CZ4CyoiqAi7gdVnmhNsS/AFV7gcz6hJ1gMdMp1oRw1KfkcZDplzJH4nhssg1nsB/XLYGMGxTh4sAqc7N3jXyE/gMWuvFU/j/VgsON0BHOFC7LrJrnj0FOPkFb2K/6wLUwgA5FnvOZMxnA+SjkGPjhi02hJI5GQV5GkCLLDNsidv365iN898ycAl1fCplu2l7KxqyPDcs4rUS8IshO8Jf8dOXPyhL3xsm85W+DT+fw0OeYb6zwqHRaMF7q3d0WGm7fcMYn1O2sEJw5t8ioXwt+55JhaWQWMrdLRUv8zDmgYi0hNTAAFXId4CkmpnU7x01AdpsI34K0jDQ== 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=SWd85zIAstAnrapTEfqyAMxGq34bG94sh3Z+CjxvV8Y=; b=VC8rU3fzNqEtXs+2umXoob4o+lobSSquCJuhjpPnGv5YLXbr+JtkfmR8bOZuKPsm0SLZep2/0D1Lz8G+wnQASKKndzFLj5L/lVIe1d82Y51LQKhgBcIQZ8H1nRkExKVNKOMMKS+3XmPxP9A3tukmbkvIkzAwRI/zBR2lav0OCErUXNe5CNTxSfZn8yGRhbJxDOUt4z3xg2tJnaTWn2lBX+38gG6romVIPmbcCZ5inaEJw1yfHTDZlZzbrVR00pBUUqHJgAVHhwXLaW33nfnJbW6ptucahwdMDIHqgf2H18M/mgYncFcZJUGGaktshuHl32yehmLowm45+GWFOJkwWQ== 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=SWd85zIAstAnrapTEfqyAMxGq34bG94sh3Z+CjxvV8Y=; b=ZDRvwzUIm7p0IkvrKSEzp7Xw+v1YPiXmksh2pi7GxOWh154bi6Vh3l4Yr1J3h3eEOUtKGL8gn5KY87rwrKaI6j9LeaD9LXlP90M8CoZZ1H/lXxgm099No+NEW7uhVzGybLW+Ic0/I+jgxiuzTfMcbilc0NfZEp6SLKmrUtfvdrg= Received: from CH3PR10MB7329.namprd10.prod.outlook.com (2603:10b6:610:12c::16) by DS0PR10MB6079.namprd10.prod.outlook.com (2603:10b6:8:c9::22) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.8835.23; Fri, 13 Jun 2025 17:58:33 +0000 Received: from CH3PR10MB7329.namprd10.prod.outlook.com ([fe80::f238:6143:104c:da23]) by CH3PR10MB7329.namprd10.prod.outlook.com ([fe80::f238:6143:104c:da23%4]) with mapi id 15.20.8835.025; Fri, 13 Jun 2025 17:58:33 +0000 Date: Sat, 14 Jun 2025 02:58:19 +0900 From: Harry Yoo To: Yeoreum Yun Cc: Vlastimil Babka , David Rientjes , Christoph Lameter , Andrew Morton , Johannes Weiner , Michal Hocko , Roman Gushchin , Shakeel Butt , Muchun Song , Suren Baghdasaryan , Kent Overstreet , Andrey Ryabinin , Alexander Potapenko , Andrey Konovalov , Dmitry Vyukov , Vincenzo Frascino , linux-mm@kvack.org Subject: Re: [RFC PATCH] mm/slab: save memory by allocating slabobj_ext array from leftover Message-ID: References: <20250613063336.5833-1-harry.yoo@oracle.com> Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: X-ClientProxiedBy: SL2P216CA0112.KORP216.PROD.OUTLOOK.COM (2603:1096:101::9) To CH3PR10MB7329.namprd10.prod.outlook.com (2603:10b6:610:12c::16) MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: CH3PR10MB7329:EE_|DS0PR10MB6079:EE_ X-MS-Office365-Filtering-Correlation-Id: 4cbf86b4-01a3-48a8-d297-08ddaaa3e97c 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?L0ZVRURPSkRMTk1mSVN1UWlwQ0o3OWduSWw3UEhVV2dxbHJ6VGRRck9qNU9Z?= =?utf-8?B?Y1ZPeFhyNDFHeXZ2aUFISGU1YkxwQ2diOEIwVGNnenYyNG0vallFdXBoaFdm?= =?utf-8?B?d1oyQU5GQ00xKzFPckJZTzI4YjZzWDNpK282QUJXN3ZRWEpGTWIwNDlVQzg0?= =?utf-8?B?azRJb0ZuVUgwQXVDS0JLODIycnVkOXhwVVI1RFZYQ1R2a3NqU1o3VlVWWmZV?= =?utf-8?B?TzZYNDdnZzBxMWxjT2RXMnJ3UHBhUnU3WDU1L1NSUTdKRGYySnA2QXRzdlUr?= =?utf-8?B?emF1NlpWTk1NYUlEeFRRZDI3YkdaK3ExMlFGdFVqM3pjVG1JRU1sZkR6L1pv?= =?utf-8?B?MHVaamN0RU82bXhXbTc1Vk1IWmFlQ2gwVEdTc0I0S3RRS0dmTVkyV0FEbzJv?= =?utf-8?B?Rm4wMEduc1BPUWhFUTFTMnN6dHdwL09Qb1dXZkVhNkNLZTlJMlprUW8zaEFw?= =?utf-8?B?WFBWZmNzNkYwbzZUSkxXVzZIOC8xazI1RE9IYSt0VXQ5ZnRKQ0UwZG1tK3I3?= =?utf-8?B?cjJmQWZoSmZ2R1NWMkdyTys0NWtDNWVkbEF3aGpEemxqVEdNSmRqSjFpTmtF?= =?utf-8?B?RzJPRUZkWFRxMXlTd3JZK0lxS2dPbDRHbDJPL0diT2NPejc3NUxPYzhMY0tT?= =?utf-8?B?M05wdTlOeVN6V1ZtV1RwYTFtTUFhMkRrcytQc25adkl3akt4bkNvVHJKK0xE?= =?utf-8?B?Wkw4VlRCOFQyNWFTRnpicnhyLzN1eDE2NzRNeUVxZHl0SWprMVN1dnNBc0hK?= =?utf-8?B?NUtIVEFzN2NSRG5mSldwTlZjWTQ4MnRiaUQ1TkhhQVNzL3BFN0RDaE50Q3JY?= =?utf-8?B?aUhJMXpuZzg0QlgrQVBDQUR3K21KWmpOZjVVQ21xd0NkWEhvUFgyNWlXcFFI?= =?utf-8?B?MEMwcmhISHhRV0ZkMitXblpHUmlBVXR4djVabXkwYXVxcWV6eXJzNFBXMjI3?= =?utf-8?B?VGNveEtpOHRWT3B4dS9sZGdOUWdGYjRXM0RGY2cvSHUrNWFtWjZ3VjFNUnVH?= =?utf-8?B?ajU1bkJ5bWNTRkFrNjlRWG1OSCtOSW11QnBQTEdIOS9Ka3ZFS1U2RUsxelZR?= =?utf-8?B?dFlZa2JLNHJaM0xxYkw4ZW9WbDFoWjdONmp6SkRGOHhpRndNN2RLR0hNWUIy?= =?utf-8?B?bHIvM0lBMHhxakNtYjVXOHlCZWZqTmExUnpGSWxBRzdHa0w3NnArdGxqRndI?= =?utf-8?B?S3d3UlJOL2tBMTJzVkh1R2luM2lCZER5dUFLbk9pM3MzS0d2bC93aURuNzRN?= =?utf-8?B?L2thdUZqUm8zVWF3UU1vR2h1MmJpWFJPVitIOHpjRXJUMjZZREhOUTJQRSto?= =?utf-8?B?dGNGaFo4UU05Y2hzVnpWWTJXZ3l2UzZsdXAyZllzZzY2SFlrVWpORFZhWUxu?= =?utf-8?B?TFhOWVZ6aUIrRGMyTWhhOUV5RTY3Z3RMTnREZ3RScUhFdko2UzcrQ1VoYnVK?= =?utf-8?B?WVFWRjNlekFqNjQ1U3UrZE1DMlhMRDMwZE9xSENHVksweE9hclp4U1RMZWVD?= =?utf-8?B?enVuaUVlSExzNldtSXltY1MyaHBuaFIwSXhqcWU3NThPSzBUK2NrcmRhdzY3?= =?utf-8?B?c3pvMnJ0dWptUU9rRFU2c3U1Q3JzeFEzaVRuWWdSSFgxbUxkbEpaUHp1Qms4?= =?utf-8?B?MkdEQ1UwOUlXWGJUSjBYWW1GalZxd2xTWldCdEIxdVZjZDBmQW1wOU14eFhk?= =?utf-8?B?NUEvNC9WRlpPWXBrVTU5aG1GajFlWmdZME1aRUlNU0FFMFNJUnBoRGJKNUR5?= =?utf-8?B?RzRNSlBvbHE1REwyak1NRkp2ZmFVRnZRdk1scitUNmV5UFNkMGRxek1zaDlC?= =?utf-8?B?ZW80dWIzSUJMWUtzVTlJdHBGeGpaeFRYc011bDJsbm42Yzk2dXhNeGVwWHFF?= =?utf-8?B?QjZwMU54VnUvcW1TM2ZRRzAyMzBXL0cwRlBsc2RRcVVYMC9sZ21lVlFSemNK?= =?utf-8?Q?qKrFx9VfFB8=3D?= 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)(366016)(1800799024)(7416014)(376014);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?utf-8?B?Tm00T1l1ODdldGpod01BZDE4UllJeXNNYjA1WVJlZDlXVktXWThobWlKaGRw?= =?utf-8?B?VUJDVVlBakdXSHlzTXpWSnFMQkJ4aXZ5Zis4UnRtdHN0dGdtWHoySFFhTC9W?= =?utf-8?B?SVdtcENlSmhiSllnT1RrLzVXNG0rdDlTYzJUNHQ5ZHljc0JWZ1c4THpKK3Z0?= =?utf-8?B?Vkk3ZmVvblBwaEpvRFhsaXJnZlQ5RW56Rm5MTUkvNU1aTS9RWmFmMTFnVFhu?= =?utf-8?B?VTFNQzEvTGw3WXF5aGlvU2tUVnR3MmNuc09vK1puLy9GbmphdTB0VEMxL0VE?= =?utf-8?B?cE9KTktnOWNMdlg3R3lsbmJHVDZKVlJhZ2tUZGVFSXRJcUFRTHRTWWpseTJS?= =?utf-8?B?cWdvK3lGRTlTbXJJZENuRkVpdlNYNlRFNGYzRVZmNXB0TkRJUUd0TC9XTGpj?= =?utf-8?B?bEk2SlVucEhxeTlKZzQwUlRWM1VEbkNwMkdwblpOeEtOT0V2WGhnRVkyblh1?= =?utf-8?B?KzVtWWJ2Z1RZc25vZjZ2Q2pJeElVNFQ0VFJwaGRLYXFaUXd4aGxvVlB4ZU44?= =?utf-8?B?S2FJMUtXSWt6RFMrM2pENHVVYWpEN25qdjRiWEhiYldRMEdBSzFsQjZ5VW1x?= =?utf-8?B?cGtvNXhjcjNBNlJSbGpIdEp5ajlQT2dFYnhtMHRpSFFUTmtuVWVMNjR3alV5?= =?utf-8?B?a3dJcE9ENXB0b3FsZXpmQ1hvRE1MNWQzQUdjazAwMVlZSDljalNXajdxa1N0?= =?utf-8?B?QW9oMk9Yb1pGLzFUQzlZUlphdTUyTXVRcTBsMkhTdmRBcDRLRzRJcCtNU09N?= =?utf-8?B?TXZCeDR3ZW5tNXVHUVFoSU1zTmFhNGJsY3RVankrYy9oN1FwYitwL0dZZXVl?= =?utf-8?B?eVh0SVZNN3FqUW1ZeHZyNS9IVDhXK3ZUMjNJYjVabFdzWjBCa1A1dWJvNEl0?= =?utf-8?B?WldSbng2K2xHa3cvY3d0eXFxVXJYM2E2dDZLY0pNc2VvaHVQQVUvcmVCTnZZ?= =?utf-8?B?eXMyZng2c00vZWE2RXBUdXQxM2NKS1BDTitWamI0bjV6OXVuY3NNR1VjdlJh?= =?utf-8?B?Nk40eWtRdkw2Yy9FTjEwNUhQK0NEU09scncyUm9RRVp2S3FwZTZSRWloRzBy?= =?utf-8?B?cHVlUkE1Y09TUytCYmU3c2ZTNFc3V3F6dVpRY3Q5VjN0RjlUdjc2QzhvZ2VV?= =?utf-8?B?SGV1bkhBRW81NDBQUldjbVFPNkNWeW54bkJMdG5rUXBlcGsyM0dKbTZUN3po?= =?utf-8?B?OENYV3BKeGxBOVFTbXQ5aXNOeGU5ZWlpeHlOWnhoVkJubFFaRVV3RDdUcE81?= =?utf-8?B?MFE3ZWFWejhwZHRJRkhSdW5NOGZBQU9ocC81NzFVdEpTbUFCd2pBVlU2Sitw?= =?utf-8?B?MWZDUlJJdkN5d2NMSVg5aGk4K0h1bVBBdzFQMEFVK3JTUXB0QzB1YmFPbGNF?= =?utf-8?B?ME10elMwRHZDQWgyNHdQZVl3U0dpeFlwZ2llZ1I5b2Npbm5qMFV2c3RLenhD?= =?utf-8?B?clZwblFobWhDcUNoWWNmaUJlUFEwOUUyc2RHRkZvOUVMMFI0WHN6YXU0Ykd0?= =?utf-8?B?dW1wTHpNT3FPaXZaSkdCK2VHeU5ZRGl3ejA5ZXFEd2RtamR6OVhudVgyUEN0?= =?utf-8?B?c2lXMXllM0d2VnQvejNLUVZpd3pYQ0xsZ1l6RDVzQXBVZkRZSDQySGY5b0lm?= =?utf-8?B?VmsySXRnYnhHckNCemVJelVuK0NTSWFxU2QyNlJLd1RiM3RxKzBpS3doZ09j?= =?utf-8?B?ZnFpS0FjU3JHZnlLenE1WFRlanAxTlZXeUI3KzErZHVjWmpPTlZxWFpvRUgr?= =?utf-8?B?dEVrUHZDV0s2YmJkbDJZbDNRMFZZWGdZRWFmUk9vRUlOQ292R1hDT290Tlcv?= =?utf-8?B?RU1FSzc1QU9yK1cxVHl1YUN2R05xdzF0bHd1Smo4Y0FoNWFoMXZrS3VQRkVr?= =?utf-8?B?V1Boa09VeXdBQmtpdGFwNEpENXRxOVlIc3BxMk82SGRMQUl4UVpRcTY3N1ls?= =?utf-8?B?VFl6SkQ0ZHB0NUh4czNkSlhwZnpoNkV5T2tUc3FUUzBmemV5Nk9xNElTUnV5?= =?utf-8?B?SitBUi9uKy82VFdpUHp4S29mRHpsMU1MR1BuMCtzS2V0eTRoVnFBOTFJV1hi?= =?utf-8?B?bW1vYVRGUTRGeDBRdW93SHB4ckU4a3Q0cmhUeUI5elcydnAvRThuMm44cXNL?= =?utf-8?Q?8Arh02EnKmCGFBAjQ9yleU8Jm?= 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: 4cbf86b4-01a3-48a8-d297-08ddaaa3e97c X-MS-Exchange-CrossTenant-AuthSource: CH3PR10MB7329.namprd10.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 13 Jun 2025 17:58:33.1394 (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: gP/bVreBSB6U8NQoNWoaon+YX0bbg7SU9oHDIyglNFVTB+czq4UB4KtuwNG0N6pm7LpJ/5ET9+qklOZuWTEv6w== X-MS-Exchange-Transport-CrossTenantHeadersStamped: DS0PR10MB6079 X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1099,Hydra:6.0.736,FMLib:17.12.80.40 definitions=2025-06-13_02,2025-06-13_01,2025-03-28_01 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 mlxscore=0 mlxlogscore=999 bulkscore=0 malwarescore=0 suspectscore=0 spamscore=0 phishscore=0 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2505160000 definitions=main-2506130127 X-Authority-Analysis: v=2.4 cv=fdaty1QF c=1 sm=1 tr=0 ts=684c66cc b=1 cx=c_pps a=zPCbziy225d3KhSqZt3L1A==:117 a=zPCbziy225d3KhSqZt3L1A==:17 a=6eWqkTHjU83fiwn7nKZWdM+Sl24=:19 a=lCpzRmAYbLLaTzLvsPZ7Mbvzbb8=:19 a=wKuvFiaSGQ0qltdbU6+NXLB8nM8=:19 a=Ol13hO9ccFRV9qXi2t6ftBPywas=:19 a=xqWC_Br6kY4A:10 a=IkcTkHD0fZMA:10 a=6IFa9wvqVegA:10 a=GoEa3M9JfhUA:10 a=7CQSdrXTAAAA:8 a=atXGq9EZXVyr5DEGGroA:9 a=3ZKOabzyN94A:10 a=QEXdDO2ut3YA:10 a=a-qgeE7W1pNrGK8U0ZQC:22 cc=ntf awl=host:13206 X-Proofpoint-ORIG-GUID: NNObb22OFGbD4xwkm4YonCzpbuUgHSAP X-Proofpoint-Spam-Details-Enc: AW1haW4tMjUwNjEzMDEyOCBTYWx0ZWRfXx8p7Q2D0QmjQ djpj+E6EKd3+NDVRMy3MnJijo54g7ci0/WG0KMNVj4G7K+6g6ObPICi9T3/92PHSwhLaumYLdcH GT8jvEDJqLGe5La9WjPARGnVX1FJT6Qi4pmxNix/Q/VV5zRaLtvFpNcgQ2Zu+1pgE6sgoRieEur phTvdQATPCKLzNMfJ2uP7ujdQchjl5M9tQTVk/8mJlif0SLe1eJS7sXNrhSd48urF9yLLH4Akh5 dg/V6PuNC8i21ZjhBJ7TueFpXzjoHky1DSCkCO/66cI+8Cl320RZNAOr1IRGPYkcWdQqE4AkaKr x+v34ogbaGD2HepIi+DsykPXoJYPN9Zm8FV0OrssF4CtXSRdSSbU5K/t68UW4Ibuj2Fb2yhWsYi w2zrA0bwZFKwZx28C+hKrX/d7CDkp81F/HtgcZPqIZe+zU2s01a8RtS2rb8LRDptAbWer/Te X-Proofpoint-GUID: NNObb22OFGbD4xwkm4YonCzpbuUgHSAP X-Rspam-User: X-Rspamd-Server: rspam11 X-Rspamd-Queue-Id: D16FC1A0005 X-Stat-Signature: 5cbb41e9t3tifmbpoxi9kowhsxd93jhk X-HE-Tag: 1749837526-981955 X-HE-Meta: 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 BM3YJZlE 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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, Jun 13, 2025 at 12:42:22PM +0100, Yeoreum Yun wrote: > Hi Harry, > > [...] Hi Yeoreum, > > Allocate slabobj_exts array from this unused space instead of using > > kcalloc(), when it is large enough. > > > > Enjoy the memory savings! > > > > [ MEMCG=y, MEM_ALLOC_PROFILING=y ] > > > > Before patch (run updatedb): > > Slab: 5815196 kB > > SReclaimable: 5042824 kB > > SUnreclaim: 772372 kB > > > > After patch (run updatedb): > > Slab: 5748664 kB > > SReclaimable: 5041608 kB > > SUnreclaim: 707084 kB (-63.75 MiB) > > > > [ MEMCG=y, MEM_ALLOC_PROFILING=n ] > > > > Before patch (run updatedb): > > Slab: 5637764 kB > > SReclaimable: 5042428 kB > > SUnreclaim: 595284 kB > > > > After patch (run updatedb): > > Slab: 5598992 kB > > SReclaimable: 5042248 kB > > SUnreclaim: 560396 kB (-34.07 MiB) > > > > This saves from hundreds of KiBs up to several tens of MiBs of memory > > on my machine, depending on the config and slab memory usage. > > > > Enjoy the memory savings! > > Awesome :) Thanks :) > [...] > > #ifdef CONFIG_SLUB_DEBUG > > static unsigned long object_map[BITS_TO_LONGS(MAX_OBJS_PER_PAGE)]; > > static DEFINE_SPINLOCK(object_map_lock); > > @@ -1307,7 +1350,15 @@ slab_pad_check(struct kmem_cache *s, struct slab *slab) > > start = slab_address(slab); > > length = slab_size(slab); > > end = start + length; > > - remainder = length % s->size; > > + > > + if (can_alloc_obj_exts_from_leftover(s, slab)) { > > + remainder = length; > > + remainder -= obj_exts_offset(s, slab); > > + remainder -= obj_exts_size(slab); > > + } else { > > + remainder = length % s->size; > > + } > > + > > if (!remainder) > > return; > > > > @@ -2049,6 +2100,21 @@ static noinline void free_slab_obj_exts(struct slab *slab) > > slab->obj_exts = 0; > > } > > What concerns me about this patch is the case where !memcg_kmem_online() and > MEM_ALLOC_PROFILING is not used. > With this patch, obj_ext can still be created even in that situation, > and as a result, if data is overwritten in the region previously padded with > POISON_INUSE (before the patch), slab_pad_check() may no longer catch it That's a valid point. I think allocating the array from the leftover space can be deferred until either MEMCG or MEM_ALLOC_PROFILING actually requests it. > If this's ignorable, feel free toadd : > > Reviewed-by: Yeoreum Yun That means the implementation will change a bit, so it's better to drop the R-b tag as the new change may invalidate "Looks good to me" state. I'll Cc you in the next version—please take a look and review the updated version. Thanks for reviewing! -- Cheers, Harry / Hyeonggon