From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from LO2P265CU024.outbound.protection.outlook.com (mail-uksouthazon11021086.outbound.protection.outlook.com [52.101.95.86]) (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 BE83139449C for ; Thu, 15 Jan 2026 13:22:36 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=fail smtp.client-ip=52.101.95.86 ARC-Seal:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1768483358; cv=fail; b=fa6ieyQ7MqSskggpAsomiiw5+rjwO1Z/lQn6y9UQCSLkstWZUxK9fujFBKwZiaRR4Vid6p8m64EJvSiezqBWpIykejl96JdkMglTouldizXy566L4FBrSIwjbT9w5kk1rvVRJ4ew6a1jC9JHrAhhq0mYd0lkhWXUDSuip36fgJ4= ARC-Message-Signature:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1768483358; c=relaxed/simple; bh=J9CyJOJqMWaEwoXrq3o6ga6w2RYwVD7+dhB93Z5HJNY=; h=Content-Type:Date:Message-Id:Cc:Subject:From:To:References: In-Reply-To:MIME-Version; b=Zf10YVPvWXRgePon12QECsUSH/mAD3/bFyJK+nBPcVIVUxzJLIdeWFAvQ3CH0uUpZADQQIcM627klJZzttqu+rIwQNlP+lNyo8WjdO8f2B1+rwmIxr3pcf+8C/rCOyTyaLLl8FixZmOPwN4i62iVZ1iysVSLG38N+AQhiecoDag= ARC-Authentication-Results:i=2; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=garyguo.net; spf=pass smtp.mailfrom=garyguo.net; dkim=pass (1024-bit key) header.d=garyguo.net header.i=@garyguo.net header.b=VWO2NkmT; arc=fail smtp.client-ip=52.101.95.86 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=garyguo.net Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=garyguo.net Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=garyguo.net header.i=@garyguo.net header.b="VWO2NkmT" ARC-Seal: i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none; b=zE9rIw2eUeOQjIL7o4ZbX5lDBqivXT6qrpMGs4v6KDgfe7ZifGz3sf87V99vuwoqrdCO1WQDj/mpLLtjq9vTXZ7LeJETTzP0Hwd8CQMforyRg2jacDROuI5g2Z3+Zy/yj6Up2ViL4xNgw1pnqxN9PJBFn42cBSfTjXUdYFJFvvk4T5PiBx05C2qHMYfyzi6Vir10Jt4BxSz2CNUCc6h8sPjt0+izkgV2GcTXnyu5RB6t8i2TtVDm1Ox1HsIJeDgbJ5zYkqxBh4KJnRvtGr9KH8FzTgtDWjlRWoDQPYlJ5E8HCDa6P+zvDTLOYdcCA2ySrgPYbiDxl5eA/xmQguBdLg== 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=2zonkAcxb8C2j4z00e4Fzl7HIyRUp78tI/2Alr8qV7E=; b=rKkXMlheTEwnabBP8WWG4dVRIGuNDb29AZL9UMSYVrnRFgqmLvsPF/4kJODv0fUY5+TLc/UpQP6ir3dW+Dt5c0UhFopBBYnZXKEVeQk9gPueTDnLe7+5wZjFJYTiXXNCitcTmhIJUa+/UoYwJlqegvxxhYLY3V506mwubF1Vkk9M1Coe5yaxhIZtyOMttoS16Io4IazzG/o1jDjMjv2rXajyHwKmJ2wlhHcRs+uPF/kbZvbhS4aWT0X2mvB7ILVxzcs0yJeFDr//v1ZZTfk2+Z3afNsk6qVzb4UbKgNJYLKh32d8UXsC72qYVL2Mo9P5/hRYd517tdwmSoBN1+2N8A== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=garyguo.net; dmarc=pass action=none header.from=garyguo.net; dkim=pass header.d=garyguo.net; arc=none DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=garyguo.net; s=selector1; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=2zonkAcxb8C2j4z00e4Fzl7HIyRUp78tI/2Alr8qV7E=; b=VWO2NkmT9x+mReSVqj/K2AO0FBFQAejZLvdjep7ClikCmKKFWlDwVWiBL89H2UzI9OIwhjt+CHURd84+J5KYgu1297GCSrH4pY69z6TNJ19x3PEZny5ZIuqOntD8xsfeMOGxkC+IutnvAg0qqPsK9x+G4p2L6OkLvXjr5ZeVu8M= Authentication-Results: dkim=none (message not signed) header.d=none;dmarc=none action=none header.from=garyguo.net; Received: from LOVP265MB8871.GBRP265.PROD.OUTLOOK.COM (2603:10a6:600:488::16) by CWLP265MB2337.GBRP265.PROD.OUTLOOK.COM (2603:10a6:400:68::11) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.9520.6; Thu, 15 Jan 2026 13:22:32 +0000 Received: from LOVP265MB8871.GBRP265.PROD.OUTLOOK.COM ([fe80::1c3:ceba:21b4:9986]) by LOVP265MB8871.GBRP265.PROD.OUTLOOK.COM ([fe80::1c3:ceba:21b4:9986%5]) with mapi id 15.20.9520.005; Thu, 15 Jan 2026 13:22:32 +0000 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=UTF-8 Date: Thu, 15 Jan 2026 13:22:32 +0000 Message-Id: Cc: , , , , , , , , Subject: Re: [PATCH v4 1/2] rust: sync: atomic: Add performance-optimal-integer-backed Flag for atomic booleans From: "Gary Guo" To: "FUJITA Tomonori" , , , , X-Mailer: aerc 0.21.0 References: <20260115021230.3297420-1-fujita.tomonori@gmail.com> <20260115021230.3297420-2-fujita.tomonori@gmail.com> In-Reply-To: <20260115021230.3297420-2-fujita.tomonori@gmail.com> X-ClientProxiedBy: LO2P265CA0128.GBRP265.PROD.OUTLOOK.COM (2603:10a6:600:9f::20) To LOVP265MB8871.GBRP265.PROD.OUTLOOK.COM (2603:10a6:600:488::16) Precedence: bulk X-Mailing-List: rust-for-linux@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: LOVP265MB8871:EE_|CWLP265MB2337:EE_ X-MS-Office365-Filtering-Correlation-Id: 43be559b-4759-4690-6e79-08de543923fb X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|366016|10070799003|1800799024|7416014|376014|7053199007; X-Microsoft-Antispam-Message-Info: =?utf-8?B?cXFiSHVzVjB3TEJ4ZEw1aUJ5ZU01TFBmNXRZVEFEN1lQWGJDcHJ2S2EzaDJx?= =?utf-8?B?bFdOYXQ3dWtybElJMm9xNlJ3a0MxVFBlbm1hS05jYUVPY2kwVDF1bWdzWVdF?= =?utf-8?B?NTVHdWhqWUNEOVovYlJ4aUhKSHVUUXczZnhjZWp2VXk0bWFKUXZwTWFWWW1x?= =?utf-8?B?YlFqYmlHT2p4cDRydjBaUXNoaGRVK1dEYmZLSjlQNURnRGpSbGhhckNGMExV?= =?utf-8?B?aXUwYVdGTE9Qd3ppQXMxNU1xclhDb01NbE1hdkt4N3k0cUxFTG1kK2RBRGti?= =?utf-8?B?dTVNMXdmSWoveG1jRnE3bGJxSDB1VzBBTlRSaklxSCt0VC9GSFgzblJSMUdT?= =?utf-8?B?SEJrR0pmR0YvWTQ2UTBuT2Q0eGgrMFJXdXJqRVY3N0VZaGFOK0dxUGxIallV?= =?utf-8?B?VGVhYXAyMFZlR2dONm04WUZDT2VkMXBXQUZVNkd1VjV6MkptQ21PcGI4Z1Z2?= =?utf-8?B?V1NyekZ1aDNuM1hPb0ZtbS9qQWk5NVB4WllSTisxTy96Tmo3VVRYVlVLWG0v?= =?utf-8?B?TW0vRHdITFVsMkN6elJwZDBPdWkwSnl4enZOczhYNk1LOHdmMEFMVFoydDdI?= =?utf-8?B?WmVaY3MzKzdyczdkWXlXcXRqeXB2ZG9hYWwrcjExRkVOTlNQYXkxUCtFNjF5?= =?utf-8?B?LzJPMHFQY2g5djJYbE1MZmxhTU5VRW5qWWFieUY0OFlLbi9Yd09wVmgwMzhW?= =?utf-8?B?NXluOWlWdFVBdkJSd1VkNWhER0hKMjdxWFkxc1BMQ2M2bjhjWFpYMzdxLzc5?= =?utf-8?B?QmMvdzhXQkVsOWZxZG1jczdQbXVLSTd3RFRZL2VkbUZEZEZaWm5GR3hUR2Js?= =?utf-8?B?SnI2QUtGRlduOFY4MjVDN1l0WUFpd2ZqOTluVGJJTWF2dE9LTmNJSE5nNitl?= =?utf-8?B?dytlcklQd1hjOXJMdlAvWGhReGRCWEVKTjNzaTljMUt1STY3OEdQSS9KaFpI?= =?utf-8?B?QXNxNkFVb3VLLy90M2dHUHFKRXpUWWd1VDJlbjBiQTAzOGZWWGYybWVRdWdz?= =?utf-8?B?Zm5NSDM2b0xiOTJiSXIxN3B5TjBXL2w5WTd3WWcweHQvZStNRmx2cWNFOU1P?= =?utf-8?B?b2FsR2ViTVZRa0cxdlVtazdPOWhZRzJaejhHLzJpT2R3dFc2N29jbCtqajRp?= =?utf-8?B?UWlRZG9WQms5NTJDSlA1S1QwOTBFV1NxdmJsTmpqd2h2THZWdGVxdzdxYjUx?= =?utf-8?B?ek5yUmtyVC9qUVlzWkJNc3NjamdERCtqKzNsb0IvTTMxYTBBTFhicUorMzc0?= =?utf-8?B?REFVa1NCV2NsOEFaaE9RRXZKQTJGYlpsVzdUU09ncVFTZkdBV2o0T2lza1pR?= =?utf-8?B?dDR0YnIvbFlBbkY5c2xhNWUrdDdOak1JTXBrSjRhcWdTZ3lBWjU2V2pnaEUw?= =?utf-8?B?OEQrTk9VMGdtb2hqK1J3NDlPWjJGZGpVQUpMU0NBbEdLVTdUakVsemtXRUdt?= =?utf-8?B?L3hkODhsc0ZkNUpFdEhXVFY5OXpIN1ZYMms5aEdHZVp4TTV3NXQ3Q0NOT3pB?= =?utf-8?B?aTlXdGVOVEhqVFpMUm8zcUNWalZ6WDAvRXV1Z2FaUnRrNlMrYUtWVTFCd2NE?= =?utf-8?B?SjRCODZmS3pMQlpWUnlOcDlBR2xMaW1IZUszUGVoRVJ1RldkNUVQK0RKekVC?= =?utf-8?B?b0l0b09UcXF0c3VVMHFIZlNYSVVneGxtVWRDa2FlaVVHWHBleWhCME94Zklu?= =?utf-8?B?R0ZhcG8xS0VYeWwwdG5jVkJuZE1Gd0l3NHBwcmtYcEdaaHQ0K0QyZXIveC9u?= =?utf-8?B?bXVNQktBaUNsaW9qbHlyc3c0ZFlKUmtGVy9IcW9tc1RvUzAwUlVQMjJHeEs0?= =?utf-8?B?QUhTSk5ESXpEYkJ3bHl5cEpaVExpalhML1owTXZObEY5c1owaEptOGd4SjVG?= =?utf-8?B?OVE2WFNsRlhOVWJ3WU5iNU80Zm5JREdETG1xY3NyQWtFUlVCSFBVODJaUENB?= =?utf-8?B?NitwK3pJZ3dPZEpHTlNNaTQ1SkkzL0ltWHF4N2RwcUpTTTcxNm91OExjYlRk?= =?utf-8?B?dDJMVFk4WmNMSFRMZEczbjhraml2RHpaY3BmUFhyYzF3dE9RbC9BMTIxL3g4?= =?utf-8?B?eHk4SzNaa0FNTkZuajZjblhiQUNnU1ozVzVSeExKWlFUYUljdGFDa3l1Q2VO?= =?utf-8?Q?IQTc=3D?= X-Forefront-Antispam-Report: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:LOVP265MB8871.GBRP265.PROD.OUTLOOK.COM;PTR:;CAT:NONE;SFS:(13230040)(366016)(10070799003)(1800799024)(7416014)(376014)(7053199007);DIR:OUT;SFP:1102; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?utf-8?B?VzNoMmlOaVBDQVptalRUVWZyQitqZWNvMDYyYUtpS0d1QnZycWhWZ294Zk5O?= =?utf-8?B?RFkyZDNic3VYZzlicUkxT3dERVRKV1d3V1AvTzhiQTBseDBkVDV3UEtobVBH?= =?utf-8?B?b0dDT0swc3JVZEg5S1pRam9BWVo2Z0h5UlZ4S2FuWEpXeVViTU1IYVFaK3JU?= =?utf-8?B?WG1yNVBodFl1ZUVPL3U2ak1FVWVIRFV6aG5rcXJRbFFKYk4yaHVXM29WTlY4?= =?utf-8?B?RGxCRUdKOGs4MU1LdU9iQU8yU0g1NWUzbTBwbGl3V2krZFZtOU5WaUh0NG9N?= =?utf-8?B?a042bFpTOTA4WVNIL2ZJOWlBcjFMeGZCUkNoa25nRFhmalRZb2dzMkN5UExy?= =?utf-8?B?dE05aUZBcHB3eWlwMnJsVFRjQWhoQ0JKa29lZkhKVUVLVzFtOTJCSHUwTjNQ?= =?utf-8?B?OWg4ZlZ4MEswV0Zxa3ZrdEIxZGM5VVRsbjFjQmVQOU5ma0pWdmFSRDRUa0lQ?= =?utf-8?B?ZkNXam9tdmh6eFkvWWlGeU9ZT0NZZ0dsc1NMOXRnamRZK3dGN2NCb1MvK2pO?= =?utf-8?B?TUx1SHVjMXJJYkkrRzlLMnlYTVZWVlRRSnpIQkZhcjFwcW9CREppc0x5a2s4?= =?utf-8?B?SVc2Z0UvTjJwNWJ3enU0YVlBZWJTWE5nUldFNWxlRlZURktjZXNadDlRUUow?= =?utf-8?B?dDMzR0ZYMU1WUllNejZQR0cveDhKZlJkUlV2VS93QnRmZTJyejY5dlFoeXd1?= =?utf-8?B?QnFvK3ZrM3pKNVlGWXpsR0VmRjlTdEdyYzhnemd3eERUWktVa1VZdk56cG5q?= =?utf-8?B?YzBCNTRJM1RQNy9qbWY0UnBlYk5jbXgvSUtZc2hHaGs1bTdGMTBUNm9QaFVT?= =?utf-8?B?TGZ3TFRwQllDV1UvRTdReFJ4dUZMK0xSMlNIYmwrcTB1WnhUbGFHYjVna0hO?= =?utf-8?B?aUJIT2xaZmR6U0NMOGEwclQyMHBYckFWdWZFMjRSUG1yd3NPODdlVXFKWndI?= =?utf-8?B?SUNRa1ljak5IdWVIMU5vQm8xUnBjR0JEcFJGVUNpTHVZQVViKzhJV2JNbE44?= =?utf-8?B?bm9rR3J3YWJha0JJUFZvQ1JIWERnR1l4aTY0bEJFNklzaC8vUWp5TmxBU01q?= =?utf-8?B?cU85d0kxNzVEODlQR1RkWFVFN01DL2xTUWVyMk1ETnQwc2hYUlFYNW0rVTBX?= =?utf-8?B?akNlN3I1d1BmTktvOGRybDRCTWFTYW1vdnVFR3JlWDhCV1RyS3VsYnZLbWFS?= =?utf-8?B?L0tpNE9aSVlNZFNiVXZYZlg3WmRGOHV4S3hmTU96bkVpeUMvd3d0SVAvY1Ir?= =?utf-8?B?YzNxNGdjSGg1K1diUlJkZUx2OTMvTVhOMFoxQzNUSWRzODNwS2k5ZDRrUVF5?= =?utf-8?B?OVdWdDNMVGhqRXJ0LzNoNFp1aTl6ZzQ2WTROUFBKKzl5RTZXUElxR1pkRHcw?= =?utf-8?B?eXcyK1BmSWVSM0tmNVVTRFNzSkd3SVZFSHNYMHZCZjc1T3diUUNkSjh6OTEz?= =?utf-8?B?cWtwN3FHRjVvN0tsV0RpYTFPQWx4Y1JTdXRvR042RDZhQmJVNWNxdFVnclNQ?= =?utf-8?B?bmJzcURPM0hQdzQ0bGxhZlVjTksxUkU1K254RGpIYjNlOCtmN3ZXOUxuV3ow?= =?utf-8?B?Z2pnbENrRmQraFRCYUY3dW5mN1pKa0JGaHk2akhYVy9rWnp5MUxDTHBkSFg4?= =?utf-8?B?R1VRWVZRY1BRQlV6endvY1dJbmRwOVFSVzkrdGJ4SHBiM2R5b2VablNiZG1Z?= =?utf-8?B?dkNLdW9pN2lRc2l5NjhrS3IzL2ZBUzlIZXZYSE5Hb3JXTWNVVHpqTEJNdW5T?= =?utf-8?B?Ty9WcWNTbm5EcVk1d3FHRE9Gckh1RGlkRndIOHhCQ2o0dXpTaFhrUzdCaHFh?= =?utf-8?B?RkZaZEhoZk9FN0g1c3ZqdFBuYU5QNVJqck1aR2ZnOEFjbXJ6RmVyY2pWQnJN?= =?utf-8?B?NDZVRUkydFRWcStqcm1rYWU2VjdaVk5yY3VYckVsUmFKWWhobnRsUTkzZy9E?= =?utf-8?B?OTJ3RFU2SUxCRkV3Z1dhVW94M2hVSmUycE1ZN1hsMnZiN2F2b3lpRzBlK1I1?= =?utf-8?B?SGNnOTl5eC9jTUxRZWRSV3NuMkcxK3hJSVFpaFBvWkl3TXBrazdQYVhJQnNa?= =?utf-8?B?Wjc2TzFIeFpTUXlBVWhubEtKcEhXWk5qdEJhcHh1cWI2cXA4TS9BSnZCRVIx?= =?utf-8?B?UXIzMHhvemtqSjVoNzNGSTZQOUR3NkVUZ2tqQml5dUkzcXJzOGRxVkc0MzF4?= =?utf-8?B?bFJUTUVRc2tEWENmbURIekRrT1o0YmtKYlJxekdNbUUxTjVSSGxMMUFBNVRT?= =?utf-8?B?WHdSRkpBWGxjZ0ZHSVR5TUlLTGNQSUY5clhFZmZCaktNUlVnWWVXQjc1S2ha?= =?utf-8?B?c2xYaE81bVh5MlJwUkN6UUdsTWRxaXd2Y2VZVGluNGl5MitVNExHUT09?= X-OriginatorOrg: garyguo.net X-MS-Exchange-CrossTenant-Network-Message-Id: 43be559b-4759-4690-6e79-08de543923fb X-MS-Exchange-CrossTenant-AuthSource: LOVP265MB8871.GBRP265.PROD.OUTLOOK.COM X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 15 Jan 2026 13:22:32.7388 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: bbc898ad-b10f-4e10-8552-d9377b823d45 X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: Bq0XJt8dVwC/WUEVyxk8ww79/QUe+fe19bVIPHS8TkuE64Ue1zNd0Ir6agdRVJlREjJVaVx8uu93upWdiCQ9EQ== X-MS-Exchange-Transport-CrossTenantHeadersStamped: CWLP265MB2337 On Thu Jan 15, 2026 at 2:12 AM GMT, FUJITA Tomonori wrote: > Add a new Flag enum (Clear/Set) and implement AtomicType for it, so > users can use Atomic for boolean flags. >=20 > The backing integer type is an implementation detail; it may vary by > architecture and change in the future. >=20 > Document when Atomic is generally preferable to Atomic: in > particular, when RMW operations such as xchg()/cmpxchg() may be used > and minimizing memory usage is not the top priority. On some > architectures without byte-sized RMW instructions, Atomic can be > slower for RMW operations. >=20 > Signed-off-by: FUJITA Tomonori Reviewed-by: Gary Guo > --- > rust/kernel/sync/atomic.rs | 71 ++++++++++++++++++++++++++++++++++++++ > 1 file changed, 71 insertions(+)