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 B2AE41487D5 for ; Wed, 29 Jan 2025 15:30:15 +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=1738164618; cv=fail; b=GSW2kLKY+5PNOgVjSTACBvWICrCxJtDyNNpim/pIRVVdUZr8xdnxSnEZUrahTE5zuntMa6War2Lk5/XJlTQf6m5Hsr78q6IwqynaB3kvB3lEKOAANjNkTJ/Htsk70KQE5vweFNzcMSHRHQtdRsjlBTdMR7q2mbAkSMXz1Ngbz94= ARC-Message-Signature:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1738164618; c=relaxed/simple; bh=bkMsdsghG4lHSDOIDh3pNs4gdhovLg/5iDEyfpypySQ=; h=Date:From:To:Cc:Subject:Message-ID:References:Content-Type: Content-Disposition:In-Reply-To:MIME-Version; b=KgiIjzIi3ne5oAg6YVMD1aYbyvx4vctBZzMo5KQAetmrYSyaRZeHL6ufmG5wY7CjqPM0GbhdDTdG7C8odbjLOuHe2VGpGmHYE9K3c0kAed7KP7VTWe6sTfEA8Ue4lK/tsxqJB+GPgNpELOBe/tbwYNggtL5K07PZBgUaBbFgV1o= 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=Bnont2j0; dkim=pass (1024-bit key) header.d=oracle.onmicrosoft.com header.i=@oracle.onmicrosoft.com header.b=jdAnFCtI; 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="Bnont2j0"; dkim=pass (1024-bit key) header.d=oracle.onmicrosoft.com header.i=@oracle.onmicrosoft.com header.b="jdAnFCtI" Received: from pps.filterd (m0246629.ppops.net [127.0.0.1]) by mx0b-00069f02.pphosted.com (8.18.1.2/8.18.1.2) with ESMTP id 50TFMuav026635; Wed, 29 Jan 2025 15:30:06 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=bkMsdsghG4lHSDOIDh 3pNs4gdhovLg/5iDEyfpypySQ=; b=Bnont2j0jEg2DkVzMj9MIOGBKdkBdob3nX C98YUN/Sh8ozpo1Jz+a9r2h1AnDcDfYhCaRT0e658uQ0egSJvzKBcFWUqx0gDNKx I9etrHNLNVmb/ehC1tbsbAyhNaOJURXskB0bCWHtZjzsgCgPBSka7AHygsKx6xSr EvpjLPFuePQK9hT9YDQfCx1VMuWyhBJBq2OKvIhYReinrWcjpdUK5Uqt5sFwfG2x WGRn1VOgdxwL1YtL4Sk+UoPw3YKWi/k5uthMyADMMttc6kvovsCHa6250Lzx2G1A esEx5EtwAbr95+qCWI0/KneVvdWSm0PAkDdyXn80/+GfdX+AtQhw== Received: from phxpaimrmta01.imrmtpd1.prodappphxaev1.oraclevcn.com (phxpaimrmta01.appoci.oracle.com [138.1.114.2]) by mx0b-00069f02.pphosted.com (PPS) with ESMTPS id 44fpu5g0y4-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 29 Jan 2025 15:30:06 +0000 (GMT) Received: from pps.filterd (phxpaimrmta01.imrmtpd1.prodappphxaev1.oraclevcn.com [127.0.0.1]) by phxpaimrmta01.imrmtpd1.prodappphxaev1.oraclevcn.com (8.18.1.2/8.18.1.2) with ESMTP id 50TETe2a036366; Wed, 29 Jan 2025 15:30:05 GMT Received: from nam02-bn1-obe.outbound.protection.outlook.com (mail-bn1nam02lp2047.outbound.protection.outlook.com [104.47.51.47]) by phxpaimrmta01.imrmtpd1.prodappphxaev1.oraclevcn.com (PPS) with ESMTPS id 44cpd9u2xf-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 29 Jan 2025 15:30:05 +0000 ARC-Seal: i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none; b=FY58vEVqr7HRHKfah+ynvCO9RrxWY66uWlopNC/Sp1FS3XbH8TkJGJEohH2uE8ekjzEczPKFA9aLXL1Otk/dharM3m7RCaQO5LQq6lq1IzO/zBF/E3RljJl9zMe0AtJPJh3x5eQ42GjiCRH8o6lqFENAPWgRl+wXGTIHwPXqKoiG8DTJ4GBkdt6vVdq0ibJBF7X6L2He8H1c4pqoOb7nr6OP8QMFMwbojgXFWkVO8jc7mZSfKp6s47O+YSRSfCPfOBEFrCndE4K7GRNGbSEE5X7zqU2frPvoPNXEYT+JtOEzoqMZ5qmw5SYtqITT3QPxzd1IMOuIn7bzeMStmmTkyg== 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=bkMsdsghG4lHSDOIDh3pNs4gdhovLg/5iDEyfpypySQ=; b=mKbKltK+GRnSDm1aeWkxCLcMnItugYzIWUxDhVuW3z1SnzSOQZmUuSKkDIgZ1G7jPYKg0Y4YzkIOTFVOaGKo3wDbhOqb8WSERTb2hwFi6flsegB/vW5YJeIyfSI6OIZJQ6cDoIb0x3+7PXH/rWcxz8wYK9NflBpHagLnLFtGNYSgKo8k0b9zYquanGS3KAc71ieMIJXvsOgg/G8v5RFCSGX/4GbUdi+c0YHeMK2zAfQauHkcA/tvlkBdQHE7Ox6Ys3dkcn21nIqQlmSENKTD0G/sDsE3aZJaqRPn3is46s8RwpAOfLCPbUcdHJ5vnqEOGjwgoimVDLwByXzxeLtNHg== 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=bkMsdsghG4lHSDOIDh3pNs4gdhovLg/5iDEyfpypySQ=; b=jdAnFCtIQeTxWOl+Vn+ph4TSyna4krKFy+cPnGHeX0I13DrWvjOly9uFHYsygnqKcScsp1BJINmyWrBjqHyrN/yXy7OMvTGHt+P3a44tYmwwL+fOjBJXgzxp/h4mW3g7xfu2aincpaFZcfCIwAggQwQYKtISLggKXRL+Ejs/rTk= Received: from MN2PR10MB3374.namprd10.prod.outlook.com (2603:10b6:208:12b::29) by DS0PR10MB8198.namprd10.prod.outlook.com (2603:10b6:8:1f4::13) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.8377.25; Wed, 29 Jan 2025 15:30:03 +0000 Received: from MN2PR10MB3374.namprd10.prod.outlook.com ([fe80::eab5:3c8c:1b35:4348]) by MN2PR10MB3374.namprd10.prod.outlook.com ([fe80::eab5:3c8c:1b35:4348%3]) with mapi id 15.20.8398.014; Wed, 29 Jan 2025 15:30:02 +0000 Date: Wed, 29 Jan 2025 15:30:00 +0000 From: Lorenzo Stoakes To: Vlastimil Babka Cc: Andrew Morton , "Liam R . Howlett" , Jann Horn , linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 4/5] mm: make vmg->target consistent and further simplify commit_merge() Message-ID: References: <829048d075d18dd34572f330d17af66b8cff8441.1737929364.git.lorenzo.stoakes@oracle.com> Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-ClientProxiedBy: LO4P265CA0168.GBRP265.PROD.OUTLOOK.COM (2603:10a6:600:312::11) To MN2PR10MB3374.namprd10.prod.outlook.com (2603:10b6:208:12b::29) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: MN2PR10MB3374:EE_|DS0PR10MB8198:EE_ X-MS-Office365-Filtering-Correlation-Id: 7b1bb990-1b3b-4c7a-8af4-08dd4079cc75 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|1800799024|366016|376014; X-Microsoft-Antispam-Message-Info: =?us-ascii?Q?GXIUtGs2UyxL8sjy/U2apiytnl72xV+LI3pDNIuspp6tW7845tipwJkrrlWP?= =?us-ascii?Q?5Y7lgqSUQNk088nr1+BwIgm4/swqmZr0LGBDmlBIa+CDE7TXSUuyBjIla8pu?= =?us-ascii?Q?T4ZP/Ups6smH2/UVQyPgeBOWldsNt/0IYdKN9S+82dezx4buNdtP62QBpVm6?= =?us-ascii?Q?P2tTO629Hn8P3Yxw3lMRbOTtsd5WvPBRcFAci+JIRZLBq0x0NNpaDfk3Lp4N?= =?us-ascii?Q?zQ4n62nc7CpW79SYF+tFz2jESiGDooHxLfrgDBlhGri8tsbPr6/uPyRR/8zx?= =?us-ascii?Q?hpB7jIEQrC9KTKya2mEEFFsVq5EAeZvlBY5ilBdCrk73WqqqeZtOBrzh4W8r?= =?us-ascii?Q?fPxJjiaoQYYUGm//uTUCJVpHoLTLbr1YynhGwHdX2HYqnmLK12yLRucd/Jw6?= =?us-ascii?Q?sXRdbRVDEQufLEy898gymfF//yPLtFREbWSIe9ejPTkcUy/e9OZSzG/XuNLY?= =?us-ascii?Q?6Ap7V/WSafUfJfdFLchdOEANPk9TS32PeOJjnsB7El+zf9QAPcaQPfIgH9hI?= =?us-ascii?Q?HaUKPJt8M2hAcx5v1T4y+wzymHt1pC1HnQGEz6FwyZ94G1KQFU3uEm71FuIA?= =?us-ascii?Q?XVNr7UJ4ysByP1WyFGgnmGSrs15Ttd4GsNWVm3qM7aH0NhQ5gyZmgOFhnvVf?= =?us-ascii?Q?5t/eXXilLng/5O6YYjpJIaX+3/FhauynceP6+wxFdGK9sgCHZJ6zpjZlO+GB?= =?us-ascii?Q?ki8zyeHDyAtCzjLPewVKKkkCZoGAV98GadES4dq2A3FMmJTHOtYkLqSMCCKC?= =?us-ascii?Q?KwbDtiU6fFPVqvhqL1OPfeUnBSHqUxBaETtyHFBJ7FogLt+YtLSlde9O/j2U?= =?us-ascii?Q?bKNuzvYVxeYBVXNue+PEpBFzO/d72l2YVjjtKnUph5cpfjRTlKIAZPxsy6EL?= =?us-ascii?Q?Udfi0tIx9cmU5Lz0TCeQabbFeDyKppaBtQ3GhA9ZEQ7uW5xFLHn0DtVL3qMD?= =?us-ascii?Q?a9LgY6Q/tjBJqHeyG5bTKexwHiRoKdXXOcFVnDKRScK6K7Ej7O1l7tw6wf3G?= =?us-ascii?Q?ysWc8bn6O3bOBnvZ3lowB/Uoo4nRshVptauR80Jc9xzVxrNsf1jEmVD6HrWH?= =?us-ascii?Q?YVq4KQBIi4VGISHiqaNPTlfw6Qc+5Dwu+CH3OtKJPDqUJncqIGRtDh7xysuW?= =?us-ascii?Q?gwQLBxfAmwD9Y9XG0LjF2Ed0lcfjtBhMVYaFZRCIkyBEs0XoaskOJ6S7HraF?= =?us-ascii?Q?Z/7jtVsY/ySBK2g9ZKES9DZewvbWlce9zBZyIWU35ROl0ILOahGc+Iz9spyW?= =?us-ascii?Q?0W+swIZJIWcGtXueLJ97a54gvRxqCIezHWLRwNZuXjeTgxNJSMYLDZQC995G?= =?us-ascii?Q?+h76YgxwDLPMdogxAewTv/671en3aTVx3lk0JVq1H59WDqxgDvvsDCc6dDeL?= =?us-ascii?Q?lGrAbEDzwAgxXTsfYR33zwhpvbCI?= X-Forefront-Antispam-Report: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:MN2PR10MB3374.namprd10.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230040)(1800799024)(366016)(376014);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?JEavU0yLdBn8U4n5yDqJdSlFxEbj/4iHRkC77Hh5fhqt/NncaOpuPkkCPpY9?= =?us-ascii?Q?xkf3ni+ynGo2/R1FYj5u8/qqtslpC/Em/t7k0VBBqnwNOPdSBA1zgyGYLez9?= =?us-ascii?Q?JbNzSQRIeXbvUFOPXe4OIoZTdSLSjU3HXK7lvAij86rPC948TU57HWRIyUpO?= =?us-ascii?Q?5Rv7CwzpPpMtl389+6tTlcDiV64ORt6BQ5bqvF/vxOYnY0vqWciEOxT7uXb4?= =?us-ascii?Q?qyHd8TCieU9fih40s4bDjsRk0iq4FNeOokmoYZ0Rvb+twWOW6ZDNndEbBDyS?= =?us-ascii?Q?ZYLacmCbmI9DOxM0fK4Id7a6KJsKCKN3bb8IJ6W20ElXEzuNC//kuTbfmQPJ?= =?us-ascii?Q?+RiZeB/4tmgmtcSiac78jVQ5MX9YkvBjMEh9pNijpYrjL4pyviM9JQn+aFCe?= =?us-ascii?Q?DdM4lA0v8wzHGALwjSzOEvi8G4C1HqMRcuoz0VRXqoCM6/7g7moGl+Y01Zyr?= =?us-ascii?Q?lTHmwtm5HbqNOx29LFN84Wm4CudLYytgrpe7mmkSemyt0k1nkzzoGgsJIVxb?= =?us-ascii?Q?0oLo/teISjHt3sdNbYzIalWlUEF/2ufHSMvWFWMkeQELjunOMi3IltO8RliM?= =?us-ascii?Q?Zf7kIM9gFId2XPA4Nw2+Ne9l7pTuiVbfjW1reDOmx7csill57dZw631B/c3r?= =?us-ascii?Q?iMLXvsDhVgoVLg41hY9aLVXWKVko74KtC7V7CLKxBurgPc93Cyad7/+R6ZUA?= =?us-ascii?Q?hkbj3F2zJmRTIktq9gEaOdZ6Ytl6yS/l995wBD1Ueh7xnb2W26BigrMXuayN?= =?us-ascii?Q?wpyhb5WE4ZNJhJDc6CD3frOWw6yJai1blQk8kSEFVAP2SR+CIo+u5EvEwBCR?= =?us-ascii?Q?eDkwODlWWK8p9WLh3t14g5Q0MCz8C7e4YVgndwkkNzCXtfo0XTZUQw8rHmfd?= =?us-ascii?Q?lojgkQ117RnH5ApM7CG4DoalFq+R0PfZPFTQnxzP7nPFp9Mws8g5+N6kpHyj?= =?us-ascii?Q?cw+pRdEUjzVwUuEgygrIU9QVOfHfh97ZjR24MHnTYuDQj/u/y6ZiiVCKyWE8?= =?us-ascii?Q?+a5jFM3qhZmFoyPobMuANNSG9vHYLT1S7fF4mSUEBwXNEqtSNX8wxzACIAv7?= =?us-ascii?Q?ZnzIZF/w/NWNJUtD8nasJD+ijNRNMx3GeebGa/KR7D++FzukKBIrkUIMXFDX?= =?us-ascii?Q?9ML58EnjDabiR7K3NVjTX++uNdwDAoUUnkUIdWlkmKtGmqZHqjrSUhz/Oz6F?= =?us-ascii?Q?/mE0DPadt4xPsCnpnrKCfNqpF0g9j3b6ypEj3Z4KHxYLi+xgrh+Y569fIGeC?= =?us-ascii?Q?ygtHD6ar4OdG3CPMUx5qNIoDu75MGYRgO2ui7HXysWSpFjfIUPyIP+KlFl8t?= =?us-ascii?Q?FkIzNCsrqz4YWMCaUim2xoA6P6hStv7Nq3pkg8HO3AChl6apChcGj3Zllx6W?= =?us-ascii?Q?g3CrMS0DvEtL7Pln8RLi/472sXQQHYfZEirBo1Vk5Y7jn+E8XCuGxpbOP646?= =?us-ascii?Q?OhXWEg0cnbMljmAwBUWNScfPz4JvYTEtwOU8jJbQO114ncVMT+mFqAQgXz9B?= =?us-ascii?Q?YYH5o+It9Zkr/CCp6wTAj41AOtXO60UZRb8BKjO9uSe3RiFMWBvadzJuquU4?= =?us-ascii?Q?F0KhEmUN+y93/1RaKmeFs02EtKjaWSXk/x7qu3ADejdXHqq+rGhv5J4Kjtsf?= =?us-ascii?Q?KQ=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: 7b1bb990-1b3b-4c7a-8af4-08dd4079cc75 X-MS-Exchange-CrossTenant-AuthSource: MN2PR10MB3374.namprd10.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 29 Jan 2025 15:30:02.3400 (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: 8sOuOswo/pF98/dprJBTDdrli6mv8NKkPFK+hxTlg7Dk7l/9G0Xxpi+A1al9TDlt52OCFwd8iIvsS5Kj4U0X4+peaJ7Yaum6KIUrcQUQGOg= X-MS-Exchange-Transport-CrossTenantHeadersStamped: DS0PR10MB8198 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=2025-01-29_02,2025-01-29_01,2024-11-22_01 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 phishscore=0 bulkscore=0 malwarescore=0 mlxlogscore=614 suspectscore=0 spamscore=0 mlxscore=0 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2411120000 definitions=main-2501290125 X-Proofpoint-GUID: 82zsekfu4p9yozrE6UlDnSGC0tD2owRC X-Proofpoint-ORIG-GUID: 82zsekfu4p9yozrE6UlDnSGC0tD2owRC On Wed, Jan 29, 2025 at 04:19:50PM +0100, Vlastimil Babka wrote: > On 1/27/25 16:50, Lorenzo Stoakes wrote: > > + if (flags & __VMG_FLAG_REMOVE_MIDDLE) { > > + *remove = vmg->middle; > > + remove = &vp->remove2; > > + } > > + if (flags & __VMG_FLAG_REMOVE_NEXT) > > + *remove = vmg->next; > > + > > + if (flags & __VMG_FLAG_ADJUST_MIDDLE_START) > > + adjust = vmg->middle; > > + else if (flags & __VMG_FLAG_ADJUST_NEXT_START) > > + adjust = vmg->next; > > + else > > + adjust = NULL; > > + > > + vp->adj_next = adjust; > > Realized this has kinda made it more obvious that vp->adj_next is a misnomer? Well yes and no. It is badly named, as it sounds like adj_start, which is an offset, but it is equivalent to 'adjust' elsewhere. But it _is_ the 'next' VMA from the one which we are otherwise manipulating, so 'adjusted next' is sort of a vaguely reasonable-ish name. But at the same time, it's all horrible and maybe this whole vma_prepare()/complete() will be the target of my next round of churn^D^D^D^D^Drefactorings... I also don't like the various 'special casing' of these situations in vma_complete(), and it feels like - maybe we can use or adapt the vmg structure for split as well and put the vma_prepare()/vma_complete() stuff there too... Anyway. One thing at a time.