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X-MS-Exchange-AntiSpam-MessageData: =?utf-8?B?cGk2d2ZQVTZnS0oyeXhuMmR4b2NBUEdyd3o4SjkrZ0d3cThtdXNKWXRrc0FF?= =?utf-8?B?cFRlcGpPbDlrdmZ2RCtZcnkvV3c2MmNJYVUrdHRXMkREclB2R3BZSngva3Zp?= =?utf-8?B?RGpsQmtXZElpMGJEMVZxVnowNnlCZUtOWEJFOWo4ZytpaUhadk1RdnVGU1RY?= =?utf-8?B?VS96OVFCalVzY2pBaTNLWHlCclJtdnpIblN2cHU3T29yM0dHZG9QOW9nMDZx?= =?utf-8?B?c2Rkd1luV3VMWCszWkRrYld0eVpzM0kwMGoreDJrekhobFVnSHZIRFd3ajc5?= =?utf-8?B?TitBcHBVSmpNalVSOFlMcUdvaHZ1K3dYQWwxYTZ0dWszQnRQMXFjM0ZWUFZi?= =?utf-8?B?ZFZrYmQ4MzBmcjgrSGtSYjkwQVdPVEkwbU5TeisxVlBJQzZHeU13dGF3blc4?= =?utf-8?B?bHRhT01rdTZjWmZ1VE4wUjh6VTI5L2VQUzREUnZDS0ZkazJ1TjJhQ0hmWXdy?= =?utf-8?B?Q0pCVWhGMmpFUEVLcE9kRXFyb1hSRDd3VEdOL0RLSTF4ODMvOWRrMVM4cE9p?= =?utf-8?B?eUtzWXo3K0FXWXU2dmQza0hpSUpod1J2K1hEN2o4Z3piTVJNdnIybnQrWlV2?= =?utf-8?B?Y2F1b1hidXN4bHJHVEtUU2tKUjhiRkUxSlFyVnl4ck84YjRJaWJ4T2Y0WCtJ?= =?utf-8?B?d3VERmNhYmp6YzFWVW80RmRLVE9hSURqMmpMYml6MmdjRWxBN1pmMVhuSTFh?= =?utf-8?B?QnAyZkFFdTJod0UrMWJQTCsvNHlMVjd1Qi92dFU1RXlHcDg3M2U4N3FjdFBD?= =?utf-8?B?T1NDYjdIZWVMREpZZ2FVSkhkRGtSSUhEdFF1d1BSbEpZWE96Nk8wVkR3QmRa?= =?utf-8?B?L2NLNytFOU91N0U2NG9WV1cwVFlHVTUrRTFRakV3STR3dHVjRENEbGdMQkl6?= =?utf-8?B?VzRUZElOU0g2NGlYbXN0NVBQM1lLYlovMnZ1VWRNRTdZQXdZd1JlTUxjNDdJ?= =?utf-8?B?clBlbENsRFViS3dmQVNGQ1hXUWdsMGFhaS9KZStmcjdWaXVTNENFRUVQM2lP?= =?utf-8?B?aXpzcjVwRXV5Tm1xSndGTjVRcVJHcmZyajNzR1lwQnROZEYva2lYSDA5a2N0?= =?utf-8?B?MXZ5eXBLL2IxRUIyckhzY0xiT0s0MVpQamJ6c2JkQUZFYW1zM0ZjbkNkdU1p?= =?utf-8?B?NForYlVhZDY0NG4wM2grSitGRlhENE91VS9tWHBSWTRCR0pES1lueGxydWZo?= =?utf-8?B?MXVVQ2ptdkowQ1AyWUl2RGd3NG1TMHE0N1NWVkZ0akNIb1lxMExZZG1FalJN?= =?utf-8?B?N24vRFJtVXpyd2RkcVZMRzZNTEVhbnhKY0xCTVNXclc0N2hKMWxBdW1SRjFF?= =?utf-8?B?ckd3UzlzMG9obk1Fckt1UXV2TTA5dXA0aTRFdmhaeG1RQmpBWWRwb2FCMHFl?= =?utf-8?B?TXYxUXNwWmZ1S2JITFRMd09IazQrYWRTenVSSnFSRmtnc243SzBlMUdvdlI1?= =?utf-8?B?TlVPS3Ira0Q3TVZ0N0pBaDR5T0x0bUhjSk1oY1B1czM4VFV5c1BjUEdObjAz?= =?utf-8?B?R0RIaEhHc3g1aGVLTisrWVJMWC9SNlZmc1prejhLMnJwNmdJM1YySWdSdm5C?= =?utf-8?B?clZWU1JUVHZRQjNlSmdCeWoyeHRPTzFVc2ZvcFRyKzF4UzNRZXNVbmdtNStU?= =?utf-8?B?YlZkc2hYckVUOFAwNjBRSHhoYmU0NXpvcHozdVlOK0ZwRGxIMVd5WVluQjNP?= =?utf-8?B?YU54ektHeDZLdTNDNE9WdjlTakR3bkRLdHhHaWxBK0lkakR2M3dtM2tUWHIx?= =?utf-8?Q?SbQhp+x3Pgjq2P3gMi3fGmbJqvjIdR3VWp7UmQt?= X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-Network-Message-Id: 77dad0c1-b9c7-46dd-b9ca-08d925eaeb9b X-MS-Exchange-CrossTenant-AuthSource: BL0PR12MB5506.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 02 Jun 2021 17:21:55.6067 (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: Zp5LsK5rD8jI9zrYrH/zKc4lYzm5pDr/sNq3I3WAGJmQxnpoNDhCNFfKQjClrfjF X-MS-Exchange-Transport-CrossTenantHeadersStamped: BL1PR12MB5144 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Jun 02, 2021 at 04:54:26PM +0800, Jason Wang wrote: > > 在 2021/6/2 上午1:31, Jason Gunthorpe 写道: > > 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. > > > I don't see how much difference for IOASID and other type of fds. People can > choose to use poll or epoll. Not really, once one thing in an applicate uses a large number FDs the entire application is effected. If any open() can return 'very big number' then nothing in the process is allowed to ever use select. It is not a trivial thing to ask for > And with the current proposal, (assuming there's a N:1 ioasid to ioasid). I > wonder how select can work for the specific ioasid. pagefault events are one thing that comes to mind. Bundling them all together into a single ring buffer is going to be necessary. Multifds just complicate this too Jason