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X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?ShJKNBLiBmKBtuezO4CSI9e1qC/t0IUPOJu4qzezUyCGxAL6cEnp4/LI3rYM?= =?us-ascii?Q?g6Y7srpyC2XuWLfJrVrR2dP2tf07LrtWHzsA9vVVC3hJ8FSHrv6cLzq0KsAT?= =?us-ascii?Q?MqzcsHHNzvPg7qMYSvR1wuEWXzyKC6CAzW5tON0+9sv4AMze2V+CaW5W+Wq9?= =?us-ascii?Q?oHxDjlr2yVB9YQzrxqpcBGkjuWe7ohzVxzVyk80VqkqnnfENLhYT41F3oDoJ?= =?us-ascii?Q?9Ift19NcfC6G06VsrJ0fbKoHDMFPjxl8lh5AaqdteSxCtaSMRy1lB8DOmGcr?= =?us-ascii?Q?Oie+Qovm2lNGNnY8xKpQFXKax6yAHNbNp9mkXWlecStBETLa/QD60Qat8N2C?= =?us-ascii?Q?lDkhSunaHBXWJP29k/lmsS8cHglr5oh2xtZMIB41RWLpqv7GG2dqVm9or4iq?= =?us-ascii?Q?p1mwWULT4NWiE8esxt6oxO93KUbzgWLqXxz5W9Ek4hEydaHJeDW9IhcFVBiK?= =?us-ascii?Q?f0wsgiUa6buQ+HdDIAzcetVXaUu389St48Ke74yDwoZsf4/AOGowSVgfh94j?= =?us-ascii?Q?V+foXorTbXeM3foEhahCW7KJ/67FeciEUvsdo+Jg/G79viMmu09zQOCrQJfP?= =?us-ascii?Q?hxAm0iceWI35OS/AXZExJimQ2sQE6e0vJjGOxMUnv9QsYMIEeApsatFovuJT?= =?us-ascii?Q?TZttL4tunX5g+UN/44NOaiXZFGz7dXPX0aZ112063rk4DgmlB6+rsp08oM+n?= =?us-ascii?Q?/gLtcsANE6BnGQc39BVNGEigJHUNNlUF6tG/OmDQmly6QNSl6ocH0HoY9UVG?= =?us-ascii?Q?q0szy5msNWuE5b90eggCEm7OiViBFccclAioWmksoA4cuSnx2VkMnPIdTa7A?= =?us-ascii?Q?nLnN2XgqFEIK8W1t64aaiSSTPSoJNVR5tOUFTmenapaxVsrn8kK00peq6v5T?= =?us-ascii?Q?t5NUsRV3bhyNtEfWbNftHgqlnBiglIkFgOrGR1wafsNlmtopL1aGiI6WYekA?= =?us-ascii?Q?k2/FV0JkY1BK8axDfyvSJgrszlSN7Zjxs/qReopBlZeRiS8/RDsdd2QOAjxP?= =?us-ascii?Q?L0yYyrWyeShWUOcrwa/z89uvZaYJg3gJ1zE7LUfr5QzRL6ZIlqDKED2acfoT?= =?us-ascii?Q?r3CjKLWWzOYd+MwUNYyUzRvLxTDORn9Lb6DejjjDIjRBqYWIMIUDHKuprPru?= =?us-ascii?Q?y/mIvD/vCEppzTbtIdy/ZlEZs9WWm6C38LoMSQis8w3Vv1FCR5ObTEJVwqyn?= =?us-ascii?Q?A520ThDvuRGy5elAW/IMHNfgh22Be/oSDxkhSyvVtkrJ8emyMJrPcsasESu/?= =?us-ascii?Q?GweT/AZaxq7hRUsgCNSThWWOv52MC21U13oHsyo/ixFo/SfWYJy0QejwtuAL?= =?us-ascii?Q?IzPxoiZ9nJupMKPY8aHHBV5ea3dmX2ZCw+PWD7uKuCf89QlbvHZprRWgWuKF?= =?us-ascii?Q?2y8GstuQrOBUJ5A2OmOsPN3o2hN8ypdi/gF/pIQ6BITetZC3U0i9G1IYIfyu?= =?us-ascii?Q?kNMmy7cYEp73GWLdAI6eRNOETF13jRfz/LMYqer04FTNlmdbMi/rbEo61yKG?= =?us-ascii?Q?ornA1mi1p31rHmXDmE1E+gXKgzInF1tMawSeK0WsCOTVWBYZdFf/MWtn1T9S?= =?us-ascii?Q?6HU+KVU/7TK2h3rqAcWrNn0xabLlpOGsIOS68pliCMQEb0pJKIzWJebMqo3A?= =?us-ascii?Q?CnR3zK4d5k+Nc0o9BTwmGIs4uTcF94m/ZjQNbd9eE+C/QFP76ho94vIhUQES?= =?us-ascii?Q?7J3kHbD0wHWxxYMmy8izAe8OR9xFe40jOEBR6F0s60fxlvIk?= X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-Network-Message-Id: 93374053-1a41-4011-1008-08de62700057 X-MS-Exchange-CrossTenant-AuthSource: LV8PR12MB9620.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 02 Feb 2026 15:30:32.0065 (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: oOSE9+96/Qhch3UyJ+3lU1FTvomCyzydCWVthph0FjEwlklv0lWv8ODQtm7rtxQO+ChsrQ4YIxVW26kxTQTsFA== X-MS-Exchange-Transport-CrossTenantHeadersStamped: SN7PR12MB7911 On Mon, Feb 02, 2026 at 05:19:51AM -1000, Tejun Heo wrote: > Hello, > > On Sat, Jan 31, 2026 at 09:26:56PM +0100, Andrea Righi wrote: > > I agree that SCX_DSQ_GLOBAL behaves differently from user-created DSQs at > > the implementation level, but I think that difference shouldn't leak into > > the logical model. > > > > From a semantic point of view, dispatching a task to SCX_DSQ_GLOBAL does > > not mean that the task leaves the "enqueued by BPF" state. The task is > > still under the BPF scheduler's custody, not directly dispatched to a > > specific CPU, and remains sched_ext-managed. The scheduler has queued the > > task and it hasn't relinquished control over it. > > > > That said, I don't have a strong opinion here. If we prefer to treat > > SCX_DSQ_GLOBAL as a "direct dispatch" DSQ for the purposes of ops.dequeue() > > semantics, then I'm fine with adjusting the logic accordingly (with proper > > documentation). > > > > Tejun, thoughts? > > I think putting a task into GLOBAL means that the BPF scheduler is done with > it. Another data point in this direction is that when insertion into a local > DSQ can't be done, the task falls back to the global DSQ although all the > current ones also trigger error. Alright, it seems that the general consensus, based on your feedback and Kuba's, is to treat SCX_DSQ_GLOBAL as a "terminal" DSQ for the purpose of triggering ops.dequeue(). I'll update the logic to do the following: - When a task is dispatched to SCX_DSQ_GLOBAL, the BPF scheduler is considered done with it (similar to local DSQ dispatches). - ops.dequeue() will not be called for SCX_DSQ_GLOBAL dispatches. - This aligns with the fallback behavior where tasks that fail local DSQ insertion end up in the global DSQ as a terminal destination. Thanks, -Andrea