From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mx0a-00069f02.pphosted.com (mx0a-00069f02.pphosted.com [205.220.165.32]) (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 8D91B331A5F; Wed, 11 Feb 2026 10:14:54 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=fail smtp.client-ip=205.220.165.32 ARC-Seal:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1770804896; cv=fail; b=uC2+RdNR4HK7azNdxjDrmJ8bXW8nhkwOpZf5TnR0CBkT00qeXAnosq0u7KA8EvIdrGmtV3W6ZoGgl4DMVjK5Xjw4q9CeevfHqWSg9MGJdYKcMskBtiEvn1oeSPZix/po7a8qjOxItMj9vGqVCl/d5vTDCfduy5K+gb2iAs0fw6g= ARC-Message-Signature:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1770804896; c=relaxed/simple; bh=vd3FtpKxb3bB9BUX+MyFHuAInpdSUemHQDa5AaKKmok=; h=Date:From:To:Cc:Subject:Message-ID:References:Content-Type: Content-Disposition:In-Reply-To:MIME-Version; b=uCGu4u0OFrigLSYVU8gkYwwlyM59Dcc7X9f53Z2C7hXp1Imte+qKXMAJNe/OTU1WbkuAQ7L1ycp4anez3FkBCOEzcr5aclNYYyJrUD6XrwML7DNov9HpefrcTQfB13iq7nG/zmtmynzrcJl4n+44FAhGNyW3I+FxljKxXcaPSR4= ARC-Authentication-Results:i=2; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=oracle.com; spf=pass smtp.mailfrom=oracle.com; dkim=pass (2048-bit key) header.d=oracle.com header.i=@oracle.com header.b=WLEQ6pei; dkim=pass (1024-bit key) header.d=oracle.onmicrosoft.com header.i=@oracle.onmicrosoft.com header.b=Oj+kXqiN; arc=fail smtp.client-ip=205.220.165.32 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=oracle.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=oracle.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=oracle.com header.i=@oracle.com header.b="WLEQ6pei"; dkim=pass (1024-bit key) header.d=oracle.onmicrosoft.com header.i=@oracle.onmicrosoft.com header.b="Oj+kXqiN" Received: from pps.filterd (m0246629.ppops.net [127.0.0.1]) by mx0b-00069f02.pphosted.com (8.18.1.11/8.18.1.11) with ESMTP id 61B9wNqf1815499; Wed, 11 Feb 2026 10:14:29 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=VUF4zGjKdKtqB/4mxr dEjDZ2MDWT58hrl+yYD9l12R4=; b=WLEQ6pei8AsbHkJxe5u3y0obQJnvNnP/95 495jpZyVVGyFoKG5DraTBYNn92U1O5onfeR9oovb8gepVB7eyopFN0hSRiO2LMEn 1zHa507lvgVKuosLAIC4pSZ0X8apybFgI27tWFKBZ2xQAEWgqet9SAgcCATgCo+k 3mtSKu6+sWL5HT7NvCKZpDmjfA3fBPQplWnGpG9A+UNk++MfwE0cOIZgN0Qqt5eU 6dIuIGFE7ahVp402fX7nvw4W7JbFzeFCHCjSB6Tka0MaYyR+2Mvay68FgZYyFim4 7m6CnfpCuJv2bVQBlq0Tp1ltHTmL/1Wsd1dsg7SA0YtIvAi/Y2FQ== Received: from phxpaimrmta03.imrmtpd1.prodappphxaev1.oraclevcn.com (phxpaimrmta03.appoci.oracle.com [138.1.37.129]) by mx0b-00069f02.pphosted.com (PPS) with ESMTPS id 4c5xh8wnd3-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 11 Feb 2026 10:14:28 +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 61B8bqYZ033798; Wed, 11 Feb 2026 10:14:28 GMT Received: from ch5pr02cu005.outbound.protection.outlook.com (mail-northcentralusazon11012032.outbound.protection.outlook.com [40.107.200.32]) by phxpaimrmta03.imrmtpd1.prodappphxaev1.oraclevcn.com (PPS) with ESMTPS id 4c82464a94-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 11 Feb 2026 10:14:28 +0000 ARC-Seal: i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none; b=BYhZjDTEfMcqJbI4G5sgVvsi6/W9lhu+6vb5PRNUJYELaLv4sQWkiGxnDvMWl0SkzSQDdFK2FlxL29/Z6q5ummtX0wQfvy5kX1ZTRJT4Mok4byNpkoF7H4604txiBHOg79y2QSE6UmdwPrtI+OAR5nsuQmWopGAW5JTfl4LuLPHu5CwEq1D0lXnbJTWOeka5WSz4z1Ni4arjvE2ps9bcpsYsYPToeZXVrjXant0qbhMPg6TFKUG/UnNDcPiRReey6RQRvwnz53n3fooetSTjvIosfrNrNkZAnmMkriaXMmuaWQzbAogg8Dbi6aDVwDuANGwUoyj8jVkTjj9K91qW2w== 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=VUF4zGjKdKtqB/4mxrdEjDZ2MDWT58hrl+yYD9l12R4=; b=W3txCO6ztVUP+qvhAOn/9uZM9+X3h+4v+OQMiqaRahe1Cs6M5O/2xyc1EZVfP8w7eqgsKPNBZOc2W0MvQtZGS1x9FqL19pDqxGJQSaJ7ieWOeMB8KZtD5WP9zy+DJAljQiM2xRFS+HoDQ0M5EcHg/e6m5LV3kp+l0WOGK353h3jhGtFzmoBw6P+Q08tzPw7p3qSrx4aXVPvyD6sYbtGyyUr+RpdcZy2A4jxLZljjedDq/uy6ykYC/diWN21BOTSMsFHAwKvMGGafNvath0Pfazq0xjRtxa4HRHR5UtgszgcHm4YJIjI+7Ej8Kgl6JqLO4dQ2gT4C6CncdtIQJAwRDw== 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=VUF4zGjKdKtqB/4mxrdEjDZ2MDWT58hrl+yYD9l12R4=; b=Oj+kXqiN0ED7UvuzhQ16qknndDKNkn1h/ytr7rzvsAAYhpVxWVoa/QWF1pSK49BsRmt61tYRMq/iFrbxLyRF1EV/Oxz6jPQAGxix2TQr1FnLRkqdCRg/zuv//F8ItSvChDw0AXLNW4D6DTlTYh1IRLUNkAGkm7e2buHg5RsG+hc= Received: from DS0PR10MB7341.namprd10.prod.outlook.com (2603:10b6:8:f8::22) by BL4PR10MB8231.namprd10.prod.outlook.com (2603:10b6:208:4e6::22) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.9520.5; Wed, 11 Feb 2026 10:14:25 +0000 Received: from DS0PR10MB7341.namprd10.prod.outlook.com ([fe80::81bc:4372:aeda:f71d]) by DS0PR10MB7341.namprd10.prod.outlook.com ([fe80::81bc:4372:aeda:f71d%5]) with mapi id 15.20.9611.008; Wed, 11 Feb 2026 10:14:25 +0000 Date: Wed, 11 Feb 2026 19:14:18 +0900 From: Harry Yoo To: Shakeel Butt Cc: Dev Jain , Andrew Morton , Johannes Weiner , Michal Hocko , Roman Gushchin , Muchun Song , Qi Zheng , Vlastimil Babka , linux-mm@kvack.org, cgroups@vger.kernel.org, linux-kernel@vger.kernel.org, Meta kernel team Subject: Re: [PATCH 1/4] memcg: use mod_node_page_state to update stats Message-ID: References: <05aec69b-8e73-49ac-aa89-47b371fb6269@arm.com> <4847c300-c7bb-4259-867c-4bbf4d760576@arm.com> <7df681ae0f8254f09de0b8e258b909eaacafadf4@linux.dev> <5a6782f3-d758-4d9c-975b-5ae4b5d80d4e@arm.com> Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-ClientProxiedBy: SE2P216CA0020.KORP216.PROD.OUTLOOK.COM (2603:1096:101:114::11) To DS0PR10MB7341.namprd10.prod.outlook.com (2603:10b6:8:f8::22) Precedence: bulk X-Mailing-List: cgroups@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: DS0PR10MB7341:EE_|BL4PR10MB8231:EE_ X-MS-Office365-Filtering-Correlation-Id: 51c9bf3b-2560-463e-c633-08de6956552d 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: =?us-ascii?Q?qoPBKvFEd3CXXPzJXh4qDEK8/0WLXDV8AjJY0Z1WV8lfNmXk2eo4yodiR7ol?= =?us-ascii?Q?72vMdNhHn+Kq+Ggr4E4IGYdcsaj1RkVCdc0HwQ3sR94uRQ5O2PhiQah7vA8b?= =?us-ascii?Q?BY0MlEL3RISWPTLAE+j3QbUhtPR2tZT9yeBT0jtXyD4oHAMl+VeeLDne2BeI?= =?us-ascii?Q?pRinkPVqsOUxEGu2/miPfRvRjamRESy/CiBYjjbaYg0AZtIvA9r0VFxPN6ul?= =?us-ascii?Q?viR00nFbdsY5WBlDT8sct8dXwsGHDuUuI2tzht6yYk3t8Nj9kcPBpZg25PkQ?= =?us-ascii?Q?fVJD8stQhG4nIg71PCsoRdCmTdVzzbzx4vVR21t/0VQd5TqbGOjRodZ6Cz/2?= =?us-ascii?Q?2gdKKsDSn8UfJWMPZYg4Mdc0jCob+5ybtb5e1BbX0wNLbRKo09CxMyQUM5Sz?= =?us-ascii?Q?YpiN6sq8Won+vKxZo0Qd/wO4PcVFBlx5xKSQH9TuOoib4GC9fzFEFuejb2QW?= =?us-ascii?Q?3aeQNaptHS9LynHwpSxlbKFP4fz2iR0j+xVT/zC/Jwa70ZRDlrpuIq5ikshR?= =?us-ascii?Q?vfnKQxLX7MSYUpowJxU4+JyIEJYVQfRbxe2pBeo4opNfP5zbgmDhyJGofMXw?= =?us-ascii?Q?c7YtJ36tOOYC88P6Je8StUTyIhK8wocMmKXZ2+J7GQzP5CyMPQcv+5VQIG3k?= =?us-ascii?Q?bj8GXf2HgfUplg/kGNnA885efbO88cnygNAEEnVhupYEe/EF2i/Rps7Voqjd?= =?us-ascii?Q?9gv3qIIUs/kiSGYxga3W1BTD7VBzCMAk9jJtsG5vELCMXJv18iKo9wz95+w0?= =?us-ascii?Q?vKw613X90TsHjhdM1VujlZJ2YqC0Xz0U8/2UsFIQwYUXwSjL8PWhH1fiIUdf?= =?us-ascii?Q?h1sDvNCEkdQnfICLADb9K3VXgGolQxLZV3lBVy48tA1Lw1TXC9z6ymB0uemJ?= =?us-ascii?Q?nvHJT1SI5m6FDc1ZqEZzFHKxvwgjTQ7osbyEdBsznzBtKOoa5PzGBCkkHMif?= =?us-ascii?Q?8Zwr8l4eHkXTbFs7PS2WBdPAsccGU/7GY1NlbAzR755MICrwamqDqJPYxoGm?= =?us-ascii?Q?q6M49kyWb6FdyVgg0BmCtNlBzH6TaXa1uhDXCFxZcqYKWi2t6Sa5YZgoVG5i?= =?us-ascii?Q?G8lWK6D1TgzauDY8gzIHoaQkGDZRobkpkZD6T1jc6ZqRgX9JEYVRfZD2c++u?= =?us-ascii?Q?NvfdQIKUjig5xulWyByNLttwA3eIZudyjOlx9daS8p52VUsCKYB6aFsBbdnH?= =?us-ascii?Q?EFzpe6HsOlP6YpEmQm7Zb2WRoYhvbh1DytAsbAQUgHXFGy0bKWKTCOmBdPoa?= =?us-ascii?Q?gtusbsfIFPZ22oZq67maFYdermU+bsVCfkodJMQkZvoXUbmqKmvBSRkOOBvM?= =?us-ascii?Q?4CEfeXk2RmxilISviHbCY8geLziypsRlV/20q+a0hi81qMvQMXITtw5NgpCS?= =?us-ascii?Q?VAQllL1zi8dlUYzh6hzTaUMUDKUvrh2xSa2r2xs7M+TyfprZkk7edBvbViC4?= =?us-ascii?Q?tf1cx/qHAe4yqvVJr5nlkP79itgll4h+83IK29PaPrrsgMxq8PUo2WUSdH4M?= =?us-ascii?Q?VxeQTvdTfD4GKyBZTUZC4KX2Ohg8EdeBGH8MTofuSOaxYdykhGBL/IVAddLp?= =?us-ascii?Q?UprY59xc3rk2Vy3HCxQ=3D?= X-Forefront-Antispam-Report: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:DS0PR10MB7341.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: =?us-ascii?Q?So0pDTwpJ187UOY+OXo+alFumfb6c6vtL/3eQaiU1yjZzxFQMMgqIFOkAs7f?= =?us-ascii?Q?6ukEx1I1dXAXEVgXXQHL1y7jy5ocDvsfiX/DY47fmBnBFQjo9e5cAkGwkCMD?= =?us-ascii?Q?RvRayhKMhNhJwItYrGfWOLQfVvl19MLf7JC5/3wjN6ddk7z9GJSBtCymt9KI?= =?us-ascii?Q?WEzi10sezHviWjAjbp+xsYLckFIfydm/AUEMp7OLjhq5T0Bp4uKq5XmhQcwG?= =?us-ascii?Q?l/+/aXUXyd44WEvB8Z2krCQEtJY4C7lIT/9qorOzq5UMuR8oGq5qkR2jD+tn?= =?us-ascii?Q?ZnmelqDyakh5fjeX1vF/2FeDqs5qbw6wyCVPJhib9eleRvpUm2OkESDe16yf?= =?us-ascii?Q?1oDUuDETcWEUMNdDAjua77yv9rNDnYzWqs4rXgBHMNNnIqELyU5cbjUmzSVC?= =?us-ascii?Q?Jn4aY56N3rA/23Z8fM5YkG/yVcmFgh6WaMg+/zvVIK/gxv4PeqrsDFchYc3j?= =?us-ascii?Q?771yuV/hmSI9i7oHxvhy0MOCqNvSa30MPRRZIuppiZhJqyjwTXdupU04IAOn?= =?us-ascii?Q?KEVf9UEDulxpseCPPwmgvixpCccnIL69kn4BYJdW9K4+ntQ7YR6FOwGY9lZE?= =?us-ascii?Q?f0zowlBmcbts+i7WI4K0O/2l/kYh4QceDv+J85lMaNvJU3GmznXjduIem8/2?= =?us-ascii?Q?2Ca9YyPEhUB9hP5il78DcZzaaNSimPloyNJIjQrJ/NEaLPGtHrJZKzKR9ALW?= =?us-ascii?Q?YJqDNeHpNaA397GBlH0dojEYF39J0PMkUj2pYslL2BfXlknyqGHtPfaAqfjS?= =?us-ascii?Q?uUQv2QgVpDP1TZ+Zvldd6MZdQ8xlDgwxc91RRsOjD6HW3OTKSxJ+pcUvrpP+?= =?us-ascii?Q?sfO8RW4ja5zZBJESvrsEZzIJ2hqCle9sGRdFER2Pbsftv1LSnxTmrVMx+6OQ?= =?us-ascii?Q?ozohxgLJ7GsbU9FLdMLZpczxDgWRxoFR8OyAFKvyS/gn9ccyg4FnYlW5bfrL?= =?us-ascii?Q?wer3i+VMxsRz8s+mms4BiwzLb5RamcMeZdJyiZvpxlPdKudVXNehCkWPKwYi?= =?us-ascii?Q?/gMS86KRATitU0HqCVV/ju+rlO0FoKo6OMOFeZmcvzo8CYkLzTcJI3C+xM6T?= =?us-ascii?Q?HCJziI5+kXEJfFRLPP42nvCIuzsSQh75sj/AZNahAXckcYKwLpHsWHIlNEaG?= =?us-ascii?Q?Ys01jfa7D+v3f910DTHzOKzmWyfAc/gyYPh1i2LByn791V/xe9HaUEcd7JGT?= =?us-ascii?Q?QapvwQchoGN/fpgMJP4OK+lSB0U0Ex/FbIBE2aU1K8zetKL0eeebDsou9SHz?= =?us-ascii?Q?WicL8hUC/Jjdy11MZHAWgBFjOVh0HpfCsrEL7qM5hiHEm9yFfatvxsV6RJw2?= =?us-ascii?Q?cxrRG7P8m/HYCXjb7BUQSriVc1DEhJN5OonYts2mTEFVhoO+2gPj0KNKEvK2?= =?us-ascii?Q?kGDnbkSaIVIXP3b61/WXyINKcw92HKOvICeIoJC3czF0WOFaq3c12Rq3PqIM?= =?us-ascii?Q?d2xZS2UAmA+IIwL+n4Hb3D5RZ4HbPzygHsUpKmjJyoCPbsuBvJKNmjbI0ZWa?= =?us-ascii?Q?ZwA1yNwSxOjrqw+xzuCZanUerHFGgCXSpFv0nkETjHMixb2PegPdWROo8Fyu?= =?us-ascii?Q?zi+OOJDzG6pc5YBlz8rKw2n03o3dzp7L2md/Huwl7M0lF7Z7Sgg/JSaxROSn?= =?us-ascii?Q?AHojnZXQkoFjAUWb7VD8ZePkguH2pSYg9guMzgofedI3nAKDzNg5eNRfPm0n?= =?us-ascii?Q?l3qmxsGg8/TffXiIeqKrdPJwPdptTvzMScTI8TG55zYpwnKEqTCoxj2sy+ah?= =?us-ascii?Q?4p1aN5R5rQ=3D=3D?= X-MS-Exchange-AntiSpam-ExternalHop-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-ExternalHop-MessageData-0: 7VKUTmQk6f7xD6sBGKSEP/5nkrK2BBSkIYjIyb6AkrarSs+M3KJMYBc1W4GqIgGxtwFEVWxypYlkY2xJ3mm/E+kUUFUMgsXpRt2wgg8l1Fr/F8F/I/uymfj6YjiUfKY3y8lHogfIWa9TNvNT8MHLCn1vzcaTVOAFLforacQSvNoHrqWkAFQNscilMq2fY7VApzc0UF9ziqAoTmywGGo+c6dZo0hJ9DIJrDq6zXwh6zz4ntbwdbWzvdYFoSRohoLKgUDCEq+mLFEQgrvUIii8PQoIkm9hHZ3MTyUXmP5vdxWekAWaODN3SyGlBnukv5mYbvdGN6AsAhG/CkCan2ZQvq64fNywyARs9U7t0nZw2h86HY5rG3q2Zs38GYNvoctAJUqYQEAnL42k4Db4DezxUbBBq0EeAO/9qqQwY7Y8kGeASFpmEW1DShH/6vkt9+p7xG9B3zoH7wLUWOwqQa44dYXkx8BW0aH6dZGxGrR5hO7vnTc63HlUJ9MHdy14K6Rcp/bMhtnw9cQd5zZg0FCWkNLb9bZNz1dV+C6OpQcUPM52i1H5ZtZY80fo2zSb8TAqwGG8M4GrAD233uduY7Yz47P8+pee8NvRrFAagzNTI50= X-OriginatorOrg: oracle.com X-MS-Exchange-CrossTenant-Network-Message-Id: 51c9bf3b-2560-463e-c633-08de6956552d X-MS-Exchange-CrossTenant-AuthSource: DS0PR10MB7341.namprd10.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 11 Feb 2026 10:14:25.3415 (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: 6AsCz19131zlmjKG4EE633bF4N+/zlGsSpwLU2sne8Pv3k41q/HwakqRs38DLerhnKapomk5CcnyGT8lv8oIxQ== X-MS-Exchange-Transport-CrossTenantHeadersStamped: BL4PR10MB8231 X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1121,Hydra:6.1.51,FMLib:17.12.100.49 definitions=2026-02-10_03,2026-02-10_03,2025-10-01_01 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 mlxscore=0 malwarescore=0 bulkscore=0 adultscore=0 phishscore=0 suspectscore=0 spamscore=0 mlxlogscore=999 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2601150000 definitions=main-2602110083 X-Authority-Analysis: v=2.4 cv=YbOwJgRf c=1 sm=1 tr=0 ts=698c5684 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=HzLeVaNsDn8A:10 a=GoEa3M9JfhUA:10 a=VkNPw1HP01LnGYTKEx00:22 a=Mpw57Om8IfrbqaoTuvik:22 a=GgsMoib0sEa3-_RKJdDe:22 a=5HfSyctdvlnlvKIfFqIA:9 a=CjuIK1q_8ugA:10 X-Proofpoint-ORIG-GUID: 4lyWe7Ji13YfzbRkD9otvsa_lUaSoi_x X-Proofpoint-GUID: 4lyWe7Ji13YfzbRkD9otvsa_lUaSoi_x X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwMjExMDA4NCBTYWx0ZWRfX5sVXvQzlwkUX ic8CC0S4L51hPCVLxfRwQ5iCkmPPmygvUdOz0+0xIT46Jwuxo3OMdVneGpYrEvQl+TjbDad0alI 46AiDfYQn7yui2QSn5WoOGNe8yDJ0xjsGXi09EfYswT6GdMCPYWhMBBu3TXIVFpnhsKw69/rAB1 6NGRZq9ToL3z5rJOgDe6gWz+mPC0WEPs3voKtCfk9s0fps7YvTc1evtq4h37kywGxWxDqHNqSCK 8g/jaIkR5e2C1YfVu2xhp4jcf7qYFHQzyv+dq23rH011mCE8mbbj/Z0X1EAdKvSKLIvJAZeKqqs ZiNwX7uxlCmIPKjxKbzfHb8i30d69O1ye3ZIDRG9whBCpAPigJse2EUE7Qorub4TK4A2XGQndV1 spIiNHjSAw5TpiIwtLnUxGNJB8Uy+OpZZ0avotxKdlqlTE8E8l3aC0xzZsb8iDwgYmiHJLk4+qs ED8HtyRU2k6SrD3VgFw== On Wed, Feb 11, 2026 at 01:24:35AM -0800, Shakeel Butt wrote: > On Wed, Feb 11, 2026 at 05:53:38PM +0900, Harry Yoo wrote: > > On Wed, Feb 11, 2026 at 01:07:40PM +0530, Dev Jain wrote: > > > > > > On 10/02/26 9:59 pm, Shakeel Butt wrote: > > > > On Tue, Feb 10, 2026 at 01:08:49PM +0530, Dev Jain wrote: > > > > [...] > > > >>> Oh so it is arm64 specific issue. I tested on x86-64 machine and it solves > > > >>> the little regression it had before. So, on arm64 all this_cpu_ops i.e. without > > > >>> double underscore, uses LL/SC instructions. > > > >>> > > > >>> Need more thought on this. > > > >>> > > > >>>>> Also can you confirm whether my analysis of the regression was correct? > > > >>>>> Because if it was, then this diff looks wrong - AFAIU preempt_disable() > > > >>>>> won't stop an irq handler from interrupting the execution, so this > > > >>>>> will introduce a bug for code paths running in irq context. > > > >>>>> > > > >>>> I was worried about the correctness too, but this_cpu_add() is safe > > > >>>> against IRQs and so the stat will be _eventually_ consistent? > > > >>>> > > > >>>> Ofc it's so confusing! Maybe I'm the one confused. > > > >>> Yeah there is no issue with proposed patch as it is making the function > > > >>> re-entrant safe. > > > >> Ah yes, this_cpu_add() does the addition in one shot without read-modify-write. > > > >> > > > >> I am still puzzled whether the original patch was a bug fix or an optimization. > > > > The original patch was a cleanup patch. The memcg stats update functions > > > > were already irq/nmi safe without disabling irqs and that patch did the > > > > same for the numa stats. Though it seems like that is causing regression > > > > for arm64 as this_cpu* ops are expensive on arm64. > > > > > > > >> The patch description says that node stat updation uses irq unsafe interface. > > > >> Therefore, we had foo() calling __foo() nested with local_irq_save/restore. But > > > >> there were code paths which directly called __foo() - so, your patch fixes a bug right > > > > No, those places were already disabling irqs and should be fine. > > > > > > Please correct me if I am missing something here. Simply putting an > > > if (!irqs_disabled()) -> dump_stack() in __lruvec_stat_mod_folio, before > > > calling __mod_node_page_state, reveals: > > > > > > [ 6.486375] Call trace: > > > [ 6.486376] show_stack+0x20/0x38 (C) > > > [ 6.486379] dump_stack_lvl+0x74/0x90 > > > [ 6.486382] dump_stack+0x18/0x28 > > > [ 6.486383] __lruvec_stat_mod_folio+0x160/0x180 > > > [ 6.486385] folio_add_file_rmap_ptes+0x128/0x480 > > > [ 6.486388] set_pte_range+0xe8/0x320 > > > [ 6.486389] finish_fault+0x260/0x508 > > > [ 6.486390] do_fault+0x2d0/0x598 > > > [ 6.486391] __handle_mm_fault+0x398/0xb60 > > > [ 6.486393] handle_mm_fault+0x15c/0x298 > > > [ 6.486394] __get_user_pages+0x204/0xb88 > > > [ 6.486395] populate_vma_page_range+0xbc/0x1b8 > > > [ 6.486396] __mm_populate+0xcc/0x1e0 > > > [ 6.486397] __arm64_sys_mlockall+0x1d4/0x1f8 > > > [ 6.486398] invoke_syscall+0x50/0x120 > > > [ 6.486399] el0_svc_common.constprop.0+0x48/0xf0 > > > [ 6.486400] do_el0_svc+0x24/0x38 > > > [ 6.486400] el0_svc+0x34/0xf0 > > > [ 6.486402] el0t_64_sync_handler+0xa0/0xe8 > > > [ 6.486404] el0t_64_sync+0x198/0x1a0 > > > > > > Indeed finish_fault() takes a PTL spin lock without irq disablement. > > > > That indeed looks incorrect to me. > > I was assuming __foo() is always called with IRQs disabled! > > Not necessarily. For stats which never get updated in IRQ context, can > be updated using __foo() with just premption disabled. Ah, thanks. I was missing that aspect. -- Cheers, Harry / Hyeonggon