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 7A9BEC0218A for ; Thu, 30 Jan 2025 22:53:20 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id CD5B72802A6; Thu, 30 Jan 2025 17:53:19 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id C395D2802A4; Thu, 30 Jan 2025 17:53:19 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 9F7532802A6; Thu, 30 Jan 2025 17:53:19 -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 7B5F32802A4 for ; Thu, 30 Jan 2025 17:53:19 -0500 (EST) Received: from smtpin25.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay02.hostedemail.com (Postfix) with ESMTP id 38FD61203C0 for ; Thu, 30 Jan 2025 22:53:19 +0000 (UTC) X-FDA: 83065620918.25.85DD687 Received: from mx0a-00069f02.pphosted.com (mx0a-00069f02.pphosted.com [205.220.165.32]) by imf21.hostedemail.com (Postfix) with ESMTP id B89BD1C0011 for ; Thu, 30 Jan 2025 22:53:15 +0000 (UTC) Authentication-Results: imf21.hostedemail.com; dkim=pass header.d=oracle.com header.s=corp-2023-11-20 header.b=CATsvf6w; dkim=pass header.d=oracle.onmicrosoft.com header.s=selector2-oracle-onmicrosoft-com header.b=Dg2W1QnL; spf=pass (imf21.hostedemail.com: domain of lorenzo.stoakes@oracle.com designates 205.220.165.32 as permitted sender) smtp.mailfrom=lorenzo.stoakes@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=1738277596; 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=Uu0ylInvjJ8pzuYF6LxUr815f4XZ4Y9PDmAktcs8BgE=; b=1N6DYt+gz6286MDay8X40/PVwrXm0wKEsiCG1hGRVagaIbBqs/9mOb83p8h7CV5ConikbV rhwICctSmAUi82urnSs6INn+IBBgJX6PuyZ3QbT1w6oox2LcT6nn9G7RXlUv1GPLzodYsV xlV4Tyu1td+aACcRR48fQWtb/uN7Cso= ARC-Authentication-Results: i=2; imf21.hostedemail.com; dkim=pass header.d=oracle.com header.s=corp-2023-11-20 header.b=CATsvf6w; dkim=pass header.d=oracle.onmicrosoft.com header.s=selector2-oracle-onmicrosoft-com header.b=Dg2W1QnL; spf=pass (imf21.hostedemail.com: domain of lorenzo.stoakes@oracle.com designates 205.220.165.32 as permitted sender) smtp.mailfrom=lorenzo.stoakes@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=1738277596; a=rsa-sha256; cv=pass; b=kr63C8Atjx+Dl693u1BnqV+3Z2JxxBsVspcJzqQObzauIGuUoCj+XVJ7xm0RV1YjSUYTYj vMxJH2uFIBEHK+4W7tYUV/Gi9RMSj6ROoba7HQTPigyBORB99L7A4eL/B6JbaEFVkgXK12 kTK1+87Y4v23jVuDoLx1FGLZwspb4L8= 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 50UMF6Xd020935; Thu, 30 Jan 2025 22:53:08 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-2023-11-20; bh=Uu0ylInvjJ8pzuYF6L xUr815f4XZ4Y9PDmAktcs8BgE=; b=CATsvf6w0UtPpk0UJ+9gSocN9777uapVW1 w5cJWg7jJ1hemIHkNDsKZLKkg4qoMjDzWpEQtVpkSHDkj9u/XnSuKpX44jnJ/vTY JbCUd1NAzVMVnJHUrBTJ5enEx8SUXrEYQIuxUnzWU7ro25K87NIPiYvqSM5OEJmE iVGZAsfWY6Wpgh5BergMZ3vj2I+4N+PI8u0otg0WpshEof6PTNHNS6DPvx3oQPe4 SnClxSL9d44V0H3P1TYHd3F48TaLHQkAxRsGPQmKtK8ltDhi4EYp1WfhJ4jezvMK b6I1aDCrzYX2YBWWiuSEJ1kfMBnt4PQU+tkzOUq3bhj6zl4Qn43w== Received: from iadpaimrmta02.imrmtpd1.prodappiadaev1.oraclevcn.com (iadpaimrmta02.appoci.oracle.com [147.154.18.20]) by mx0b-00069f02.pphosted.com (PPS) with ESMTPS id 44ghxar29w-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Thu, 30 Jan 2025 22:53:08 +0000 (GMT) Received: from pps.filterd (iadpaimrmta02.imrmtpd1.prodappiadaev1.oraclevcn.com [127.0.0.1]) by iadpaimrmta02.imrmtpd1.prodappiadaev1.oraclevcn.com (8.18.1.2/8.18.1.2) with ESMTP id 50ULm2uE009040; Thu, 30 Jan 2025 22:53:07 GMT Received: from nam12-bn8-obe.outbound.protection.outlook.com (mail-bn8nam12lp2175.outbound.protection.outlook.com [104.47.55.175]) by iadpaimrmta02.imrmtpd1.prodappiadaev1.oraclevcn.com (PPS) with ESMTPS id 44gg1fp6wv-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Thu, 30 Jan 2025 22:53:06 +0000 ARC-Seal: i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none; b=x2N/bMbN+RbcAXQ2+WZqpwpCoJtaugqtSUuMX5GnyJJGt68rU5j+hmJDjiXwa/X2ga5p7Mki0KM0GP8/h3st1Pj7MOFOnCDS7uY4TKcniB2mCE1DPndWl1UpPxB0XtCJJlkYai1Q7OhfPpiBICb83u7r6jiiePjT+IUulbHKykjtgciYIWHHc3J/cfxqYkZIl6XJhWxdGR9D8vI4PY5IjRmTNZf0XQoiFxujHtOCAkqnn2GIvDkh0htnSBmgB0573dAsOF8BuaSk9VIgEFgrpGFw8tjDffZHDQuhvuzQUfRoOHJ1rGoG8jw6Uf2zLP8LehOdDwBT3wF/76jS0zHXfg== 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=Uu0ylInvjJ8pzuYF6LxUr815f4XZ4Y9PDmAktcs8BgE=; b=vC7j6dU9VTYSbnerdnIOJipy3VEEIWcsvh0Hm4HkDlcnUVP0Ypb8ai8cj2k4G1T+51KdS9+3aDnDxKarLZIHUyoJSRYkaK/rOQJPWJ23c02js45i29yo/LhuDbi5xCP+Xx7UjTcIYi2YY7GQK5V6laeAfWsoImvcymgkcPY9DVd1840QucLZ+Mt6sjmFPfzRnZRiuRuPG7dYQGS0ZQX3BKuB3G5/3BX1vxpM9qzdO9oOpzxgSsfxddaOBgtLfPkjevKBtave9snFBBwqc3iLeuaMerbdyDzAzJNG6qZFYCohjpCLu9JemOwLZoEQjORSafS1aWZ+G47jIWIPQ6CHIA== 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=Uu0ylInvjJ8pzuYF6LxUr815f4XZ4Y9PDmAktcs8BgE=; b=Dg2W1QnLPiq2eUysCRZU1U2v70Mfr56hI+nYdvqrIgdcuXrb/qrNuEN5pQj2XtUaPDGEdVUX0/kGFLtLH35kwHvpA1K2Wjm1zlpNbWYejl8e2Ece6anQnbVvkav7koeZa4goHHt8/g4631F46bboriz51IRfg9DZjKewC4ljMOk= Received: from BYAPR10MB3366.namprd10.prod.outlook.com (2603:10b6:a03:14f::25) by BLAPR10MB5106.namprd10.prod.outlook.com (2603:10b6:208:30c::14) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.8398.20; Thu, 30 Jan 2025 22:53:05 +0000 Received: from BYAPR10MB3366.namprd10.prod.outlook.com ([fe80::baf2:dff1:d471:1c9]) by BYAPR10MB3366.namprd10.prod.outlook.com ([fe80::baf2:dff1:d471:1c9%6]) with mapi id 15.20.8398.018; Thu, 30 Jan 2025 22:53:05 +0000 Date: Thu, 30 Jan 2025 22:53:01 +0000 From: Lorenzo Stoakes To: Andrew Morton Cc: Christian Brauner , Shuah Khan , "Liam R . Howlett" , Suren Baghdasaryan , Vlastimil Babka , pedro.falcato@gmail.com, linux-kselftest@vger.kernel.org, linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, linux-api@vger.kernel.org, linux-kernel@vger.kernel.org, Oliver Sang , John Hubbard , Tejun Heo , Johannes Weiner , Michal Koutny , Shakeel Butt Subject: Re: [PATCH v7 0/6] introduce PIDFD_SELF* sentinels Message-ID: References: <20250130143754.1b8bb87bfb15175dd434529b@linux-foundation.org> Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250130143754.1b8bb87bfb15175dd434529b@linux-foundation.org> X-ClientProxiedBy: LO4P123CA0626.GBRP123.PROD.OUTLOOK.COM (2603:10a6:600:294::11) To BYAPR10MB3366.namprd10.prod.outlook.com (2603:10b6:a03:14f::25) MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: BYAPR10MB3366:EE_|BLAPR10MB5106:EE_ X-MS-Office365-Filtering-Correlation-Id: a30238bc-f663-497d-93b5-08dd4180dad7 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|1800799024|366016|376014|7416014; X-Microsoft-Antispam-Message-Info: =?us-ascii?Q?W0FQlc4DIicyHUS4QIZARtAhrc9vnJ9aBWkQl3BN+wegZhs3WoY6DInondbu?= =?us-ascii?Q?cleEKunx0sePIZi8MgqheDxr8oIsWkAwmBfVRpO1l7wV6iTSngeQ9RNQbyZs?= =?us-ascii?Q?V8+6F9pIdBEfEcPT6Ulbb3JIKhi0BnGHHH443yO/ljV6v7hE7Set39YDKyH2?= =?us-ascii?Q?WVh0atq0qKt0bopHL1mGiO/aE0u9jAx8wrSfEwOGvhhYifFAO/f34DrkoaUM?= =?us-ascii?Q?LnE5UeNpGfiMNMN5LRJuHbHDomMF956RdrjYnzQC+z30CcEnVs+POM/rw/Q2?= =?us-ascii?Q?bYcLX3KfY0o9JAdXm4qwVW18qmfUqZpm2TbWjiRBrxvPbwzmiSZetrW+kCTt?= =?us-ascii?Q?SL7qI3Dus8FcUK8SVpxNbslcH7PvkqApXrxt7lrfHonwR/mYccqMTdItBGOW?= =?us-ascii?Q?YRZpQSRvaoHTiPAqajhxdFmAICY7gi0KngJDl9C4a+PLF5aPtlIqsAJaTIu0?= =?us-ascii?Q?CVnT/2rCUUrIR/xGnUeOPMn+5+s61ew8lliWxAKL3P+cRWvjcjroJXqnJdGA?= =?us-ascii?Q?xZGTA8c7vAG+puqh8UzHmAFbeBX09+/xkPBLY/s9Wqq6uTyv4VpgfvOaOzCf?= =?us-ascii?Q?ARBgx+i5z9/HhWWqKQQDhI1nXH8+iDruqRJNrD6pG37+Z46Zj1SIbS5i8mtR?= =?us-ascii?Q?gHj8a+ioxCnQY9k19fg+6lfY1mCQnCTNgRwVWkrOWuWiLXXnrlD/7gnZwa8d?= =?us-ascii?Q?vssRiSEcgNfmvW8G1EzuRZo0MbtWH7CJdSdexkTavQbcPHZLbxHGNI7igrs0?= =?us-ascii?Q?8bnxCm1QmDHXNjUsFoTQg3PecovrluaELjPonGlJXlISypcV7EfrjJRRpO6M?= =?us-ascii?Q?l/Z1F98q/YOx6Hi6YvflqRvjdFxIVhNjTU0Rvo6XR90qQ+N04k3rSDLH9tWM?= =?us-ascii?Q?PVEZEB+WVaIGa9VKXKI0943CM1FVwddqlS2epb7E4aJMMmXAFJyE66Na8eMI?= =?us-ascii?Q?MgZ3PX72HpuARQVNEtcyaieheCBOoPo74gqj4RvFfnV2WgfuMBI74SREmTAu?= =?us-ascii?Q?MqiY5pSVU9Z20d6gmFx4fi72X3KUEOErV7OmD9KTMDakQYOrBUajVM4YYg3y?= =?us-ascii?Q?CbZc1q2EPrqD3WNzlwZJp4ZEbe2fqDUMhdXox7PkkZrcVJb6w+bg3ix+b6hl?= =?us-ascii?Q?nc9GPOuzsjskxw3kHmzzuETPtHCBYyhTbbLsMiKRBDBnaO126QwrvZaTIKnF?= =?us-ascii?Q?7zCwEdalLAsctch3hKndg19r7oD70rxdIY3JD2Y3zq2/x99BMa21jJm9TUW2?= =?us-ascii?Q?dx8mNbWh1o5Y3AGdSoBhfT7+qAWsKhgrotkWrgYfHQebX2BXpERN/BXwwxVL?= =?us-ascii?Q?fYTO0UoSxtIeQi2YHaYUUFKwKHO4PBI0fnYDt+CJ0QGnxm423pt86TsFcD3p?= =?us-ascii?Q?CMfVSK0AcHzFQGZdijgqBfKBpP0D?= X-Forefront-Antispam-Report: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:BYAPR10MB3366.namprd10.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230040)(1800799024)(366016)(376014)(7416014);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?vZhUYAl4KsV73UngiVyLxsmXG2sk33O0NOinRoEEuKcsXv01dq9yuAa8r95M?= =?us-ascii?Q?cHHgQ4N75QtERMY9w5YyBP5outuzsR3QfisLlx+EtnBysMyQeGcanhNH8Usc?= =?us-ascii?Q?4e25TfIIUZg0uu73p0JGResizJbp1YPYNQfiX87jb0AfHFIFfVRo1fnHYccP?= =?us-ascii?Q?KXIosl5xhZ7pjD1mn9y7WMlBoGKvUOuCR6zSp3+4x6r4uatf45COgRTARKOZ?= =?us-ascii?Q?czjmn4ScQ1LM++iAvfK526Fqz+75N5FIIwrS6dwfyoffn3T0d7OgldMKNEWg?= =?us-ascii?Q?JT8ZZ/VxUstidALVwNW82vdnhYrvKbbxS4KUqhN1OiWYG+KoX8lUZcEWC8pc?= =?us-ascii?Q?GB63mqKh3tYTKTamw22Px9IjwqvvZKaDgVonpI23WeYFQGMeIeROsHHeG85V?= =?us-ascii?Q?y/4lmxmTWyv5qja+E2XZ/0Z/Ts/COeEBViWCpcU/bPN9XVX24AVhxQPqG0GO?= =?us-ascii?Q?i/S2kl8nhVXD2vsm7PlEjAdWs8I1WxaUzAUAb2dSrpI4c5glSFSAy2+PV4n3?= =?us-ascii?Q?buR4WGpzz1UgAfAcToSm2ujaQSxB1bMZ1AflL/3MediqEbPtHJDz0BlNhMyP?= =?us-ascii?Q?G7qgktC9zamxNPsIB4hOWpDXboUtkDJZSQJPb86BJfqfnXsF1UHL0vv7E81E?= =?us-ascii?Q?57hI6almxsBs50ou9yyBFfSMTQqTNuMD2lB4xc8Ok6U9M25kArUk8AzOnHLM?= =?us-ascii?Q?RplQYrUE0/I0eRL5eAwzB+QHicPEFz+oAShlA1YiF2maGB5CKod4xElYJwoO?= =?us-ascii?Q?KjrMxGW7uNP/QjwFmUezyPDknqHJc7WZNpMpd09eYT2yIenxsQXrYw+RR1Nj?= =?us-ascii?Q?tyv3vEgQrZkM6phIBSn9zasPMxvlABbsE072QJelsyG5q37j6xK+oONiLbfS?= =?us-ascii?Q?N2SZGGn0JgpRnYdghkYnLRhB0DKOYi3heWkC+MJX0ZOxT+01D5wpaqo+Wj8m?= =?us-ascii?Q?0S4ZubTtoUVQAaJQPPQ8c3fjFf1Lb8n5n5dLmGceyM1vg9LYx/YXcYTz+KP1?= =?us-ascii?Q?QLCKaUiXVpz8quHQmNGpDGV3pkVPuPp8XNQgdcB0UYZsNQOOlp4Qq8QTCvOF?= =?us-ascii?Q?cj8DlXv0FgADQ3Qh1KPV2C7zEa45HHWQ8xaWarH3QILuEMFLaqJ9KAZvlx/y?= =?us-ascii?Q?w6KCto4OZsrJ9cz9RJYEPZUnkyXWrimH4R9lNtTbU2/LLvJ7QIcZThDgR948?= =?us-ascii?Q?IGY1gz8HMtR0xfidDy8Uz4LjNqZ5hWXfTSRrGIvwcy7zytT2Y4HDQ2hAokzW?= =?us-ascii?Q?VNMy2SVY4bb6OeD9LJmJ3v8L8z2Gz5U+A/d3q6RzZrUvvAus9wW9GTLFVgYm?= =?us-ascii?Q?qgRZb1N+A5XZ/9oCHgair5bu6GokotyVgE35Gbpasn0PmKfdzPpGQQ5zm+VD?= =?us-ascii?Q?r2CNV/IGn2ssMSOzp24vf8XA8pFSGLyh51dt4XJ7ba7aFzESQHwPe3TmfYm8?= =?us-ascii?Q?TQ5lv2NMGV6SSecwXSkOXcz5kXdxdYIJlljoZ/pMtuaUwldVwm2cOaEF5AYx?= =?us-ascii?Q?uLCtNV/yBbc0wmkDNWpKT1f5OlZ49OwuIpqu7RK/kPgS/rIdSGFdflZqFPpS?= =?us-ascii?Q?wlECIyjqaC9hhvfXldRt2PtIelwePREr5HQ55Om0CUExkA1PPfCXAnI5pW+w?= =?us-ascii?Q?eA=3D=3D?= 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: a30238bc-f663-497d-93b5-08dd4180dad7 X-MS-Exchange-CrossTenant-AuthSource: BYAPR10MB3366.namprd10.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 30 Jan 2025 22:53:04.9680 (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: Y+V97EUKRSxelvHv4/Wm8kDQ+iQyq+knyRcN1tMluwviUgzf020jzUBDnKpgpjPyzK/XwUoxl6H6GyB/esSlvY5PuqxZVIaCBTllGFofFeQ= X-MS-Exchange-Transport-CrossTenantHeadersStamped: BLAPR10MB5106 X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1057,Hydra:6.0.680,FMLib:17.12.68.34 definitions=2025-01-30_09,2025-01-30_01,2024-11-22_01 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 mlxlogscore=999 spamscore=0 bulkscore=0 suspectscore=0 adultscore=0 malwarescore=0 phishscore=0 mlxscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2501170000 definitions=main-2501300177 X-Proofpoint-ORIG-GUID: 36uB-ZsAgr9VOQphtRDsMSKw4B9l0LVx X-Proofpoint-GUID: 36uB-ZsAgr9VOQphtRDsMSKw4B9l0LVx X-Rspamd-Queue-Id: B89BD1C0011 X-Stat-Signature: 9jazadqqi8djysmajcaou4i44umb97y9 X-Rspamd-Server: rspam08 X-Rspam-User: X-HE-Tag: 1738277595-933123 X-HE-Meta: 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 kOyBxcyD 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 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000165, 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 Thu, Jan 30, 2025 at 02:37:54PM -0800, Andrew Morton wrote: > On Thu, 30 Jan 2025 20:40:25 +0000 Lorenzo Stoakes wrote: > > > If you wish to utilise a pidfd interface to refer to the current process or > > thread it is rather cumbersome, requiring something like: > > > > int pidfd = pidfd_open(getpid(), 0 or PIDFD_THREAD); > > > > ... > > > > close(pidfd); > > > > Or the equivalent call opening /proc/self. It is more convenient to use a > > sentinel value to indicate to an interface that accepts a pidfd that we > > simply wish to refer to the current process thread. > > > > The above code sequence doesn't seem at all onerous. I'm not > understanding why it's worth altering the kernel to permit this little > shortcut? In practice it adds quite a bit of overhead for something that whatever mechanism is using the pidfd can avoid. It was specifically intended for a real case of utilising process_madvise(), using the newly extended ability to batch _any_ madvise() operations for the current process, like: if (process_madvise(PIDFD_SELF, iovec, 10, MADV_GUARD_INSTALL, 0)) { ... error handling ... } vs. pid_t pid = getpid(); int pidfd = pidfd_open(pid, PIDFD_THREAD); if (pidfd < 0) { ... error handling ... } if (process_madvise(PIDFD_SELF, iovec, 10, MADV_GUARD_INSTALL, 0)) { ... cleanup pidfd ... ... error handling ... } ... ... cleanup pidfd ... So in practice, it's actually a lot more ceremony and noise. Suren has been working with this code in practice and found this to be useful. The suggestion to embed it as PIDFD_SELF rather than to pass it as a process_madvise() flag was made on the original series where I extended its functionality. So in practice I think it's onerous enough to justify this, plus it allows for a more fluent use of pidfd's in other cases where one is referring to the same process/thread, to the extent that I've seen people commenting on supporting it while sending series relating to pidfd. Also Christian and others appear to support this idea.