From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from AS8PR03CU001.outbound.protection.outlook.com (mail-westeuropeazon11012066.outbound.protection.outlook.com [52.101.71.66]) (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 F0C1D2F533A for ; Wed, 18 Jun 2025 07:17:02 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=fail smtp.client-ip=52.101.71.66 ARC-Seal:i=3; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1750231025; cv=fail; b=XaZkS8rBTytlw5P8GkNglBsxYVjMop+41L/XUReFMStLXY7vf2Tos247bhXdVkvfQ/CN8y0hDCejqJLoxAzACiR4YvjD99ITk1JmUhTfFeCMaAsZ6MZzOFTG0DeE/mra86tINPo2sm6BqczpPQNcFoNgw/T+Oc6DKffNBmQPcYQ= ARC-Message-Signature:i=3; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1750231025; c=relaxed/simple; bh=WbLYaSo83OjAnvGJZZOaDOl+aVMoywj/f0AcRZ4+7bo=; h=Message-ID:Date:Subject:To:Cc:References:From:In-Reply-To: Content-Type:MIME-Version; b=LvR+vJb/vlV1B/izi6qlN1I4pBeBsz7adyIHU9X6Clcx27VnGuM+AfIH0yuFDvxD0VEVa9kvziC5Ibxo7KGSdrHlhxOO1284G4SqWDOo68h7n2333tMUXBKtZNu2gWLDSZ4mI5TWxFXHxWLE3CKv7PTsuE1O2cSoAYdUCcdTjs8= ARC-Authentication-Results:i=3; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com; spf=pass smtp.mailfrom=arm.com; dkim=pass (1024-bit key) header.d=arm.com header.i=@arm.com header.b=jpaJAN86; dkim=pass (1024-bit key) header.d=arm.com header.i=@arm.com header.b=jpaJAN86; arc=fail smtp.client-ip=52.101.71.66 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=arm.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=arm.com header.i=@arm.com header.b="jpaJAN86"; dkim=pass (1024-bit key) header.d=arm.com header.i=@arm.com header.b="jpaJAN86" ARC-Seal: i=2; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=pass; b=zV5SVKCR045d5kH/owgvZ1ctOwFxQHw6PiKKeKN6sQu0y4YDtB3iIZLiHUzZXLbNQUBocsLHONUCebZtyI27LwTruqjAavRuybxmxX3A1TgXJDkXKycuK3DxkZNoYd7iBgyOSgk1RxGluQQstjZ00YfzhB9CkmYT2Z16P+QwPSns4fSISYVmxxE1MeUm9iF1MAsVpjdJeG9DguDx8ojNfLrV2L/nwgOhXOfpKMERaYT6Xj57TAbmcbfHmwpHPAoVnmpt95W3WC2Q8iaLeClMih4GMnpzPy79apz73Yarp7sKWvx/Sg/gp8085nOd7o4jomK1VZWFX1VsFgn2iEXLuw== ARC-Message-Signature: i=2; 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=WP0Sm/n30Y8hMg3xyFxoay3eKroXsChZHzMAar6zT7M=; b=DpJz4qB9Jivf2qZlwGnZnzraHsEPRkJVQLfekdO3aQqvYssibMRoM+NgOKsalFYPMuxKKYIforwensQ31B1Tcb72qWJEqr/VT3SLR1OArO4GdxMNsesXeIJgwnSjkTn++Jc7HSLzTFbW+M8P+IhqZUR6V88jNiESmwZxUF97oGlRo+LPRlA3JCDShbtyjqnbMlZcB/BViLMqKutBdM7c7yPVUH3ZDYFAgRX48rxBUHMq3U6AzJJ8iLjhZOPThCqC7kUMWadivvKaM6VJWVOIFOTWimC7RCD9VB5TAS0zpwUBNVSRd1lg3ZMmn+pCRvXtSgk6iC/yQZEC4K+MvraMtA== ARC-Authentication-Results: i=2; mx.microsoft.com 1; spf=pass (sender ip is 4.158.2.129) smtp.rcpttodomain=tencent.com smtp.mailfrom=arm.com; dmarc=pass (p=none sp=none pct=100) action=none header.from=arm.com; dkim=pass (signature was verified) header.d=arm.com; arc=pass (0 oda=1 ltdi=1 spf=[1,1,smtp.mailfrom=arm.com] dkim=[1,1,header.d=arm.com] dmarc=[1,1,header.from=arm.com]) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=arm.com; s=selector1; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=WP0Sm/n30Y8hMg3xyFxoay3eKroXsChZHzMAar6zT7M=; b=jpaJAN862LafL+TZ7oqUJwh23o/XQ/I8wW4+hxzhp3S+mRAwgV7RB46UwegpMGkc5P0SfgKq4g87s39Ap/IKRtp4Oqqiom3lQW+y7T9kv7KJiKXJwMfITI6oC+pCLW2ncdvLv4+17Gztv2Qrf8GsiP/n6sxFSW9/8tbUhRyy6MA= Received: from AM9P195CA0003.EURP195.PROD.OUTLOOK.COM (2603:10a6:20b:21f::8) by DU0PR08MB8930.eurprd08.prod.outlook.com (2603:10a6:10:465::20) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.8835.29; Wed, 18 Jun 2025 07:16:58 +0000 Received: from AMS0EPF000001AE.eurprd05.prod.outlook.com (2603:10a6:20b:21f:cafe::4f) by AM9P195CA0003.outlook.office365.com (2603:10a6:20b:21f::8) with Microsoft SMTP Server (version=TLS1_3, cipher=TLS_AES_256_GCM_SHA384) id 15.20.8835.25 via Frontend Transport; Wed, 18 Jun 2025 07:16:58 +0000 X-MS-Exchange-Authentication-Results: spf=pass (sender IP is 4.158.2.129) smtp.mailfrom=arm.com; dkim=pass (signature was verified) header.d=arm.com;dmarc=pass action=none header.from=arm.com; Received-SPF: Pass (protection.outlook.com: domain of arm.com designates 4.158.2.129 as permitted sender) receiver=protection.outlook.com; client-ip=4.158.2.129; helo=outbound-uk1.az.dlp.m.darktrace.com; pr=C Received: from outbound-uk1.az.dlp.m.darktrace.com (4.158.2.129) by AMS0EPF000001AE.mail.protection.outlook.com (10.167.16.154) with Microsoft SMTP Server (version=TLS1_3, cipher=TLS_AES_256_GCM_SHA384) id 15.20.8857.21 via Frontend Transport; Wed, 18 Jun 2025 07:16:56 +0000 ARC-Seal: i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none; b=MXYyrjOcSudFTrnoggn5BQ24OGUQd+J3HE7mcYFDRrNnWmsOohCB+nwILaIoV5DJDf873KN9dvAZCX7I4wAu6iw2qVLYtfovDQxmvcC9NMeh3WaNOtV/dDzoQJzIEnvMouYiu3BoOXZTobSBN/7i9dQoPb14POhbziBj9h7Or6KRhcKa63XFxzLVSMpe1iKkYJig55TIOd5f+fnnQ8zByQmd1kzF8/hRM7QzmZbGPo6Fw2Sby/IfQpgbvxZIvfmlcTfPGrfSZ9HNMBPjpgux0DVDkDl0Vu/fpqGKYGe6VsmNuisCRO+Itpvs3k41eGjkGF1Rz2ROm7y8EeZ+sN9v1Q== 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=WP0Sm/n30Y8hMg3xyFxoay3eKroXsChZHzMAar6zT7M=; b=pu6XdznFBZNGY41fDv3SzEhUXDZ6Jp9e8DGxNiO2Hw4Slr4utcb/Vq1YuNx8uhWh+4Wy6GOci0w5mwZjOdXt9aTBNbE1Iiovtm/i4GMr2T24cTqY2i+PPLvKfIvfr4Q0M8BdBkvb03qsPGoHYJHn9NoC5oKBCwetoRVB4J2zLE2oovlD7rIxByvpC3bv+2PrH4UvkFa2wWje6AhNJS2bSN+grRiVFsDC5P6TdCCGZ6DSmOw2qRPTjb+PDKlsYZaZ47mEYS/cJT7cHkyCEYZIf80qXAFhb4SqfVc6/Hou6l3CNcfdgrDNCBYQqlmWvxqg69peoEvqs8QWHSxeRifAwg== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=arm.com; dmarc=pass action=none header.from=arm.com; dkim=pass header.d=arm.com; arc=none DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=arm.com; s=selector1; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=WP0Sm/n30Y8hMg3xyFxoay3eKroXsChZHzMAar6zT7M=; b=jpaJAN862LafL+TZ7oqUJwh23o/XQ/I8wW4+hxzhp3S+mRAwgV7RB46UwegpMGkc5P0SfgKq4g87s39Ap/IKRtp4Oqqiom3lQW+y7T9kv7KJiKXJwMfITI6oC+pCLW2ncdvLv4+17Gztv2Qrf8GsiP/n6sxFSW9/8tbUhRyy6MA= Authentication-Results-Original: dkim=none (message not signed) header.d=none;dmarc=none action=none header.from=arm.com; Received: from AM9PR08MB7120.eurprd08.prod.outlook.com (2603:10a6:20b:3dc::22) by PAWPR08MB11158.eurprd08.prod.outlook.com (2603:10a6:102:470::15) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.8835.30; Wed, 18 Jun 2025 07:16:22 +0000 Received: from AM9PR08MB7120.eurprd08.prod.outlook.com ([fe80::2933:29aa:2693:d12e]) by AM9PR08MB7120.eurprd08.prod.outlook.com ([fe80::2933:29aa:2693:d12e%4]) with mapi id 15.20.8835.027; Wed, 18 Jun 2025 07:16:21 +0000 Message-ID: Date: Wed, 18 Jun 2025 12:46:16 +0530 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 2/4] mm/shmem, swap: avoid redundant Xarray lookup during swapin To: Kairui Song , linux-mm@kvack.org Cc: Andrew Morton , Hugh Dickins , Baolin Wang , Matthew Wilcox , Kemeng Shi , Chris Li , Nhat Pham , Baoquan He , Barry Song , linux-kernel@vger.kernel.org, Ryan Roberts References: <20250617183503.10527-1-ryncsn@gmail.com> <20250617183503.10527-3-ryncsn@gmail.com> Content-Language: en-US From: Dev Jain In-Reply-To: <20250617183503.10527-3-ryncsn@gmail.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-ClientProxiedBy: MA0PR01CA0023.INDPRD01.PROD.OUTLOOK.COM (2603:1096:a01:b8::12) To AM9PR08MB7120.eurprd08.prod.outlook.com (2603:10a6:20b:3dc::22) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-MS-TrafficTypeDiagnostic: AM9PR08MB7120:EE_|PAWPR08MB11158:EE_|AMS0EPF000001AE:EE_|DU0PR08MB8930:EE_ X-MS-Office365-Filtering-Correlation-Id: 988a1217-a9f0-490b-69ba-08ddae381c09 x-checkrecipientrouted: true NoDisclaimer: true X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam-Untrusted: BCL:0;ARA:13230040|7416014|376014|1800799024|366016|7053199007; X-Microsoft-Antispam-Message-Info-Original: =?utf-8?B?ZU4rR0t5c3FhdVByWEFVWGRXb3VyZk1pOGIxRHBrOUtFTENqUnZkNzhsa2dN?= =?utf-8?B?N1F6L2VQa2c0VXdxSHdxalJITjZWOU13STgxOFZWOURtZVdiaXZFTytRZ0ZO?= =?utf-8?B?VHpnM0k0U2hEWlZOT05EWEZVYXhOMzRPM2NpdDdvTHg1am1OLzlKZ2c4OUJG?= =?utf-8?B?anNIRWE3MCtyYVpKbmJiUHNtUTczWjNCbmFCZU9YRWpTNnlCNllMTmIzam50?= =?utf-8?B?MktiWk1paVlQaXNpS0xnblAwUklpMnl2Lzdoa1ZZWlduNmYxaXlScG40bmor?= =?utf-8?B?MkVNWHV2cEtWTnBxTGVobFFxR3JtbHk2YXJMRGlJUWx2S21PY3pNUDE3Z3kw?= =?utf-8?B?Y1pFanlLZXhsd0NGMnlsRXRMMEp3K3VYaUZ6L25QVG9DbWtZS0Q4eXB6VVNk?= =?utf-8?B?aE82V1ZUVGd4bHRRQW5kMlJ0SGN1QjNGRHJMNjYzS2d5clBieDNQT2RlMTVs?= =?utf-8?B?bThVa0NwU2I2TFpWNUUvajc0SnJUK2phRmJRMHEvSHlwbHdoc2VUMjZmbVBI?= =?utf-8?B?NVNuZnB6V2ZhSTF3cXpJTVM0M0xUMXZiaW4ydkNmb3BzOHZkUWx1SmhaMHFK?= =?utf-8?B?bUJYeFh4SzJVLzQ3SDhvaU85SmFRa2F6SHlVZmRkZHlaZTRUTERLRHFQL1Yz?= =?utf-8?B?Q2NTNExIaFkzR3VraExBeWhRZ2hIN01XdFZQOU5RSXBRcHFJWWVJSHQvOWov?= =?utf-8?B?RkUwblA3Y1ptWlVRbW1FSDJsVGcySFlrMkx5S3Iyc1pyZHB1WlBteXRjV04x?= =?utf-8?B?eFFMTkRhNnRTclIvK2ozQTZhQ28xSm5qZ0NGVnZKd1hQVUZIcFFRRlNsK2VR?= =?utf-8?B?VE9jZjd4cmUyYXd1Q3BSSVpxbXR3WUVYNVhIOHZPVUtpVnQ2N20vVm8vRytL?= =?utf-8?B?RXZWMXJNc2F6SVhyYkg1VFFZaDZFSXVOSDRqbzhWeDczWHZpbHc4YVVnMFJN?= =?utf-8?B?MjlsbUl5TDJVWkYyenJVa0QyeWVqdUx3dE9yVjBFeHNHdUhZVWRFRUp1VWR3?= =?utf-8?B?b3AxT0JaTGIrK3BaSnlKcnJwT3ZCZkFiVlU5dHplVng0Nk9MaUx6SVRjQnIr?= =?utf-8?B?MFpqWFErSzVjaUg2czZpSmhBSmtQVnBPNHZER3NKdk1tRXIxUUNyQmFLd2Yz?= =?utf-8?B?YkJmbGxJNDRvVzhlUGdLZXEvM0s0TzZJSXZDZE5IUXV6TmYrUkRHRzhlWUtN?= =?utf-8?B?bkhpZkh4bkxOclczU0VPdE9ycWNzNitIT0g5U1JkcE1Bc3RONDJtNk9HMjhX?= =?utf-8?B?S3piUkJCaXVkdkVNc3JXY1RPQ1duL2hPUXVrWUFkNk1UK0xYQzBPUFYvMUpm?= =?utf-8?B?Sk1Pc2ZseGFSMUwvM1NLZzh1YVFEb091VXBjOFdqcXU4WHBxeWt5S2tqSk9P?= =?utf-8?B?VEVPODFIVkJBRkFaU1phdjFmVFp3ME1udVN1R0RyZ0s4RzlINnFEbmsvcWQ4?= =?utf-8?B?clZ4d2tlb005U0g4dHpzTjhXUWM3NWc3QllyRVdHUkVnWHVZa2xiSjNGVzRj?= =?utf-8?B?QkovRkI2dTFtQU0xeFNyR0ZkRG94REJBUDl5NkcyZTUweSsvem55dEJJdm5T?= =?utf-8?B?NjVjV3ZsRTFSMmZBb1VQSDRoS3lxT0dFSE5oRnhTV21Keks4VzlacUhVRW5O?= =?utf-8?B?TmxZV3c0U0JPVlo3T1JDT0xoR3dGb3BoMVZ3VlVSRWw1N0VzaDN6K0QzVDFI?= =?utf-8?B?bFpkVjNtR0xOdWFteGdzNndSTEsxSGFhWVV1RGN2N2hudDh2ZmhvenZoN0JO?= =?utf-8?B?djNyNmFHb0NxWlovNC81bDlUaVI0VGQ1b2RKWjI4ZDBWUG5pNzBBeXo3dFRM?= =?utf-8?B?bHIzcjEwT2pJSEpBVnFZaU9qaGdDVVZ4cCszY0lFT3VYNysyVTBxTi91T2Ro?= =?utf-8?B?Qm1tR3JKeEJuRkkwZHUvb3VmOHc1UWxMK1BHQ3kwRWRSeG9CbmsxUjQ0cWpT?= =?utf-8?Q?dEIFC5pppY0=3D?= X-Forefront-Antispam-Report-Untrusted: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:AM9PR08MB7120.eurprd08.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230040)(7416014)(376014)(1800799024)(366016)(7053199007);DIR:OUT;SFP:1101; X-MS-Exchange-Transport-CrossTenantHeadersStamped: PAWPR08MB11158 X-EOPAttributedMessage: 0 X-MS-Exchange-Transport-CrossTenantHeadersStripped: AMS0EPF000001AE.eurprd05.prod.outlook.com X-MS-PublicTrafficType: Email X-MS-Office365-Filtering-Correlation-Id-Prvs: a3e42e86-952a-442f-c944-08ddae3806fd X-Microsoft-Antispam: BCL:0;ARA:13230040|1800799024|36860700013|14060799003|82310400026|7416014|35042699022|376014|7053199007; X-Microsoft-Antispam-Message-Info: =?utf-8?B?THhIa3FpY3I1M2w1MEZ6REpKNE02dFhuRytxMk1EVDJYN1FNQ2lPYlNBYm5u?= =?utf-8?B?VXZwMVllb2NNU0t5SE45aDFwa0VRRWp1RHVhOXE2SldPUTkyS285dmxNd2U1?= =?utf-8?B?OEF5SmFGSS9Xb2JMMG9IWU9LL1FJZlVGc3hDMk1PemZ4citBRis2UThVbUZn?= =?utf-8?B?ayszWE5lMzY1c2lVT1VIdk1mdCtZdStweXNLOTdGQWFTUk1kREhlRmRkdlNV?= =?utf-8?B?bjNVbkZMMFQ1dnBaeVRENlVYMElqcEVzMUxpRldhYVhmaVF3aExQR1ZpNUxK?= =?utf-8?B?djZSRzdHcE9qZGlMRlFYamdaa2MwUG44b3VRRktZZTkrMlZqUWlwdE5tL0Nv?= =?utf-8?B?T2NTbWk4SkNLYkphS0Q1UDBPOFNxT3RYS1FtUnFTTUU3TEdsb1lteG9xaUlH?= =?utf-8?B?dmZvZHpVL3NwQTRkYzJKbWpoMkF5MUZsbUdzazMxTEpEYzdJVU1VQytkUnU4?= =?utf-8?B?VnY1VjJOQzU4ZHRFWENEbUVSZTJNdW1iVUdmbkRSL3V5ZElWeGJlWTFSMlQw?= =?utf-8?B?aTRUQW1yeld0blBKTERiR0E4aHdMaHhWMk40S21laWN1b2RiRUZ0cFd2d1E2?= =?utf-8?B?OFdQQmFoMktTY25EdEFCSUs0ZlViSE52MU9oaDRMQ242VStNLzVlYnV4S2dv?= =?utf-8?B?Mkt3V0ppVW5kbWxxTE8vR3MrR1lBTExlU3ZKbmwrTmZabGJYVVYwaVduSEd5?= =?utf-8?B?SXhZV1lFdkUzSExxZ1gwYXIvemlTdjhNUktYcGxTS0dtMFZ2RlE3aUV6VDZM?= =?utf-8?B?Z2pDbjhKZmNGSURkQndNQmZidUU3RW1xTEZNMVBCREY3Unc4THphbjN2bCtn?= =?utf-8?B?M3FjS0l2RXFENVFSRUtFWkxGTG9KKzlXWDVzWnczSm13UkRDcDc3VVQwZFp0?= =?utf-8?B?cVFRcUJSaE82WkdQRGlTM3cxYXRRZ2JkWDZqWlh3S05KM2NnSDN0OVMxaEFw?= =?utf-8?B?YzFrNFZOTTVkQnJGQU5tSG1Jb2lVRDZsdS9TOVRRdzFUekVkNHAya0RoTkZU?= =?utf-8?B?c0RINHhydEl1NVdBMG1XQXRzYmxlbkNqem9KcmFBeUlJSmlBZElOOUMzL0Uy?= =?utf-8?B?TS9aWDJEdWlEVmhhZE9EZCtQQ2dIZzdvS2dWVlFBc1M1RkwwRURxV2JFT2dk?= =?utf-8?B?R212eEl5UTdZckRSL0hka1JZVlExQ3daam5xcEZrN1F4MXgwdkdSdjEraFVY?= =?utf-8?B?NnpTWmhtSWJZRUhJSFJ5YmliNzlNdEU2dGF4WTI5Mm5sN0RIdkxCdThHelFZ?= =?utf-8?B?cEE0NGU3aXBIUTRhblZJZTlkd2F6YXZ3OXdNbjNkRmhubjNZVXhXOWw4V2JX?= =?utf-8?B?anFEWmNLSTBzSEw4cWs2R0E1bldmdXR6LzlhNnMwZDBXVWdLQWlVZ2NKZU8v?= =?utf-8?B?Vm54dU95dElNcUlQSml1d1VYSUN6NEdUckpYY2dQWmdDc3BEUTMyc0h5RGR0?= =?utf-8?B?RXJ4dWN2b25ha2xNamtCQjI4M2hITlJWS0NWS0xLZmpNdzVKSTFuRHV0SG9j?= =?utf-8?B?UUNHVStNV09ld242RlQ1emdUYkhYMjNYbTMxRXg5WU1GQ0xZUGpGYllBYlQx?= =?utf-8?B?RWI1NWVmT3QzOGNhSUkrc0p5Sm1aMGdOMXRtR29DVFBVOEcxOGdTZndhc1I5?= =?utf-8?B?WWhsekpiVXdYQzJhaGRWRDIwdkZjN0Q1dk0xcGppQVZ0S3hkbkNBekNnWmh3?= =?utf-8?B?U0pYRDRSV0RJeThXaTFpS1ZidEUyekplZnRjV0tTbmNBeHRyMWl1K2Y3U0p5?= =?utf-8?B?NkU1KzVuVWZncTlVY0RDajhVTjIvTVdUU1QyeVg3aHhQVXFGMHkwYUJHdDM1?= =?utf-8?B?NEFNc1lZUUN6bGhPTHRvZTBoei9taEg4d25Kazl5WVJkVElZOUJpdzBEenNX?= =?utf-8?B?ZHBHOVIzaGVFN2JKOC85TlcwWWRpVlpzRE93K3k4OHAyVE04ZVJHZ0VwWWlV?= =?utf-8?B?RDE0Zk1vaVJqRFV0VjNjc1ptdWRKQUYvSm1ETFcrMWlJSEhYLy90OVgzdkNw?= =?utf-8?B?bDVpeklDbStJUEt5QVhIY2FZRWFWbW9UN0RjdGo5SkhuRk9aVWlXZkp6Skl6?= =?utf-8?Q?wvmDQf?= X-Forefront-Antispam-Report: CIP:4.158.2.129;CTRY:GB;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:outbound-uk1.az.dlp.m.darktrace.com;PTR:InfoDomainNonexistent;CAT:NONE;SFS:(13230040)(1800799024)(36860700013)(14060799003)(82310400026)(7416014)(35042699022)(376014)(7053199007);DIR:OUT;SFP:1101; X-OriginatorOrg: arm.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 18 Jun 2025 07:16:56.7261 (UTC) X-MS-Exchange-CrossTenant-Network-Message-Id: 988a1217-a9f0-490b-69ba-08ddae381c09 X-MS-Exchange-CrossTenant-Id: f34e5979-57d9-4aaa-ad4d-b122a662184d X-MS-Exchange-CrossTenant-OriginalAttributedTenantConnectingIp: TenantId=f34e5979-57d9-4aaa-ad4d-b122a662184d;Ip=[4.158.2.129];Helo=[outbound-uk1.az.dlp.m.darktrace.com] X-MS-Exchange-CrossTenant-AuthSource: AMS0EPF000001AE.eurprd05.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Anonymous X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem X-MS-Exchange-Transport-CrossTenantHeadersStamped: DU0PR08MB8930 On 18/06/25 12:05 am, Kairui Song wrote: > From: Kairui Song > > Currently shmem calls xa_get_order to get the swap radix entry order, > requiring a full tree walk. This can be easily combined with the swap > entry value checking (shmem_confirm_swap) to avoid the duplicated > lookup, which should improve the performance. Nice spot! > > Signed-off-by: Kairui Song > --- > mm/shmem.c | 33 ++++++++++++++++++++++++--------- > 1 file changed, 24 insertions(+), 9 deletions(-) > > diff --git a/mm/shmem.c b/mm/shmem.c > index 4e7ef343a29b..0ad49e57f736 100644 > --- a/mm/shmem.c > +++ b/mm/shmem.c > @@ -505,15 +505,27 @@ static int shmem_replace_entry(struct address_space *mapping, > > /* > * Sometimes, before we decide whether to proceed or to fail, we must check > - * that an entry was not already brought back from swap by a racing thread. > + * that an entry was not already brought back or split by a racing thread. > * > * Checking folio is not enough: by the time a swapcache folio is locked, it > * might be reused, and again be swapcache, using the same swap as before. > + * Returns the swap entry's order if it still presents, else returns -1. > */ > -static bool shmem_confirm_swap(struct address_space *mapping, > - pgoff_t index, swp_entry_t swap) > +static int shmem_swap_check_entry(struct address_space *mapping, pgoff_t index, > + swp_entry_t swap) I think the function name shmem_confirm_swap is already good enough? Anyhow the changed name should at least be shmem_check_entry_is_swap. > { > - return xa_load(&mapping->i_pages, index) == swp_to_radix_entry(swap); > + XA_STATE(xas, &mapping->i_pages, index); > + int ret = -1; > + void *entry; > + > + rcu_read_lock(); > + do { > + entry = xas_load(&xas); > + if (entry == swp_to_radix_entry(swap)) > + ret = xas_get_order(&xas); > + } while (xas_retry(&xas, entry)); > + rcu_read_unlock(); > + return ret; > } > > /* > @@ -2256,16 +2268,20 @@ static int shmem_swapin_folio(struct inode *inode, pgoff_t index, > return -EIO; > > si = get_swap_device(swap); > - if (!si) { > - if (!shmem_confirm_swap(mapping, index, swap)) > + order = shmem_swap_check_entry(mapping, index, swap); > + if (unlikely(!si)) { > + if (order < 0) > return -EEXIST; > else > return -EINVAL; > } > + if (unlikely(order < 0)) { > + put_swap_device(si); > + return -EEXIST; > + } > > /* Look it up and read it in.. */ > folio = swap_cache_get_folio(swap, NULL, 0); > - order = xa_get_order(&mapping->i_pages, index); > if (!folio) { > int nr_pages = 1 << order; > bool fallback_order0 = false; > @@ -2415,7 +2431,7 @@ static int shmem_swapin_folio(struct inode *inode, pgoff_t index, > *foliop = folio; > return 0; > failed: > - if (!shmem_confirm_swap(mapping, index, swap)) > + if (shmem_swap_check_entry(mapping, index, swap) < 0) > error = -EEXIST; > if (error == -EIO) > shmem_set_folio_swapin_error(inode, index, folio, swap, > @@ -2428,7 +2444,6 @@ static int shmem_swapin_folio(struct inode *inode, pgoff_t index, > folio_put(folio); > } > put_swap_device(si); > - > return error; > } >