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Tue, 1 Jun 2021 17:31:39 +0000 Received: from BL0PR12MB5506.namprd12.prod.outlook.com ([fe80::3d51:a3b9:8611:684e]) by BL0PR12MB5506.namprd12.prod.outlook.com ([fe80::3d51:a3b9:8611:684e%7]) with mapi id 15.20.4173.030; Tue, 1 Jun 2021 17:31:39 +0000 Date: Tue, 1 Jun 2021 14:31:38 -0300 From: Jason Gunthorpe To: Jason Wang Cc: "Tian, Kevin" , Lu Baolu , Liu Yi L , "kvm@vger.kernel.org" , Jonathan Corbet , "iommu@lists.linux-foundation.org" , LKML , "Alex Williamson (alex.williamson@redhat.com)\"\"" , David Woodhouse Subject: Re: [RFC] /dev/ioasid uAPI proposal Message-ID: <20210601173138.GM1002214@nvidia.com> References: <20210531164118.265789ee@yiliu-dev> <78ee2638-1a03-fcc8-50a5-81040f677e69@redhat.com> <20210601113152.6d09e47b@yiliu-dev> <164ee532-17b0-e180-81d3-12d49b82ac9f@redhat.com> <64898584-a482-e6ac-fd71-23549368c508@linux.intel.com> <429d9c2f-3597-eb29-7764-fad3ec9a934f@redhat.com> <05d7f790-870d-5551-1ced-86926a0aa1a6@redhat.com> <42a71462-1abc-0404-156c-60a7ee1ad333@redhat.com> Content-Type: text/plain; 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X-MS-Exchange-AntiSpam-MessageData: =?us-ascii?Q?moag02HNsczOx4oy0xg8TH0g8JOTF5drapX6F863y95tYxRcoVpasJP2bUjR?= =?us-ascii?Q?RVrCTFjQj4lEFBfkK4qZV5UFbiK6rHbhrHK7y71t7WyB9pH3BWSIXvIX/nTn?= =?us-ascii?Q?4l0tnphRwo/KtWt+Ckz/EZtdUAJDMePRTaJ2ptSNrXxpB6a9VO2oqrVLNG1V?= =?us-ascii?Q?BVFtXZPTGD1ZeeBINe0FHuyG3YXf2yKi3mUjSupd1arbgwSfBfTmFSiG5olm?= =?us-ascii?Q?NsejNXoGQ60mdFHMV44Zx53u7AMPXS5cG9CTLG1p+qDLLRaELp6UTAx6PK/J?= =?us-ascii?Q?VowHWPigfc90nfSuUmmmRZHeLOc3RQ4vTY3Gm+uGquezg3RDlDjlWenf3bJG?= =?us-ascii?Q?D+jVd0p9nfEoYCXfIGxFhEOGmUufqe0P/Lu/i4LydEPQbsUInTWWo0J7yhiU?= =?us-ascii?Q?AdL3odtTMKw7lg2GK/3XbFZw5XL0+83+XLAljkKTdL+e4NJOWmaTqMqYqOSA?= =?us-ascii?Q?TPTkEwd9o9ruKo8EBX3KeaZlu7GD+1/zDuQ6pgWZwbvN7n1kzNtRaKz6AVmu?= =?us-ascii?Q?cJjs/wOUVWrezIhZf/c/+SJUCN9M+LCN+o4SssCG2ONW/X02m1AEMOYD2kEF?= =?us-ascii?Q?4GdJu8egNGEnxa7vewT15m5NGGLKlkFMa8ic0lTyjreV6vISnNkZIGBXLUF9?= =?us-ascii?Q?1zkNzXQg3gV72Rg14Y5/iCR2f55McWx6ovqBgcar7+V8uX4XWHpOAmgxrMS0?= =?us-ascii?Q?67Twp96bJB7dn0zVSmJxuRR5AbcTzv5KIYmSUeRG/87wUYd6LtZL0zYu3Beu?= =?us-ascii?Q?xOtU9XUxdXw0CeL6qOuyjAH8doMxqDFeiMpeYE00KfTjrJGb1T+WdpG6OOcy?= =?us-ascii?Q?kRSoRRPrUYL7w4KGcKY/iHJShFlxJ6Z/oD1JY3SYmnsEqioDShP6P2vEaFlg?= =?us-ascii?Q?WzNPIhhk7KTCFKSFAaMunfKzwsZNz1a0JnJo9OQRHlKktcCSjLMVFPuTWIMQ?= =?us-ascii?Q?BZJMmR0msqmU9iyYKdvjNDav75LrMJz6LZuby6WQ1Uk7artdMQUie9n0yjo6?= =?us-ascii?Q?KwL9KeRZR+TCIzRhj5JdAAp+/tQeMPFRf4srdnmv7sBWwCKXGMZzxArYa6bN?= =?us-ascii?Q?s70ynXcN2GcANeALKzuL65L1yebv7kYe9OBZJXik2AelPW8eXcDA7K9sZKE6?= =?us-ascii?Q?LmiO94DPn/A3ouLXcwzCcT6/I3Fb8K27A3O30Qy2SNwjyvtRGK6OBrrFTY8B?= =?us-ascii?Q?zcrHSSns4l1adsGqgeq6MJ1HQufdShov9nDdsVIxUhJI3oZ2gj9S0ZMwMeil?= =?us-ascii?Q?/7WlrbokVHKNB2IxmtKg7SBXOxewviIKA5T551QB0hbG9tUkUTBdRh41N0mr?= =?us-ascii?Q?fTsN397RlWPQj4GTemOBP7hk?= X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-Network-Message-Id: a748361f-51c6-4edf-572e-08d925231ceb X-MS-Exchange-CrossTenant-AuthSource: BL0PR12MB5506.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 01 Jun 2021 17:31:39.0258 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 43083d15-7273-40c1-b7db-39efd9ccc17a X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: 70veIwYQy21gQcG6B05Y8P+MfLTnpGZMHqDzz3oLNnrontTQgAg1qg7n+RCbfq8R X-MS-Exchange-Transport-CrossTenantHeadersStamped: BL0PR12MB5505 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Jun 01, 2021 at 04:47:15PM +0800, Jason Wang wrote: > We can open up to ~0U file descriptors, I don't see why we need to restrict > it in uAPI. There are significant problems with such large file descriptor tables. High FD numbers man things like select don't work at all anymore and IIRC there are more complications. A huge number of FDs for typical usages should be avoided. Jason