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The next version skips it for an attach that reserved the bandwidth. > __dl_task_bw_move_cpu() skips move on spanning cpumask The attach reserves nothing here, by design: the root domain that counts the task stays in the mask. If the task then has to leave its CPU and lands in the other root domain, migrate_task_rq_dl() moves the bandwidth there (patch 23). So total_bw stays right. What is skipped is the room check in the root domain it lands in. That is the same for every move without a reservation, as patch 23 says. The next version states it in this patch's message. > per-CPU reservation mismatch when task_cpu() changes Thanks. The window is real: a wakeup between can_attach() and attach() can move a sleeper, and the reservation is then not used. But the bandwidth does not stay in the partition. The task's CPU is out of its new mask, so migrate_task_rq_dl() moves the bandwidth when the task leaves it. total_bw ends right. What is lost is the admission, in the root domain the task lands in. It differs from the one reserved only when the destination spans two root domains. This is the same as for a task that changed its affinity or its policy in that window, so I leave it as is. Thanks, Mathieu -- Mathieu Desnoyers EfficiOS Inc. https://www.efficios.com