Power management operations using ACPI can trigger a context switch using kernel migration thread on isolated CPUs

Issue

The isolated CPUs experience a context switch to migration kernel thread and back like this:
snippet from ftrace function_graph plugin trace

        ...
           <...>-60731 [005] 369249.338552: funcgraph_entry:                   |      __context_tracking_task_switch() {
           <...>-60731 [005] 369249.338552: funcgraph_exit:         0.055 us   |      }
     migration/5-35    [005] 369249.338553: funcgraph_entry:                   |      finish_task_switch() {
     migration/5-35    [005] 369249.338553: funcgraph_entry:                   |        vtime_common_task_switch() {
     migration/5-35    [005] 369249.338553: funcgraph_entry:                   |          vtime_account_system() {
     migration/5-35    [005] 369249.338553: funcgraph_exit:         0.024 us   |          }
     migration/5-35    [005] 369249.338553: funcgraph_entry:                   |          arch_vtime_task_switch() {
     migration/5-35    [005] 369249.338553: funcgraph_exit:         0.024 us   |          }
     migration/5-35    [005] 369249.338553: funcgraph_exit:         0.477 us   |        }
     migration/5-35    [005] 369249.338553: funcgraph_entry:                   |        __tick_nohz_task_switch() {
     migration/5-35    [005] 369249.338553: funcgraph_exit:         0.036 us   |        }
     migration/5-35    [005] 369249.338554: funcgraph_exit:         0.948 us   |      }
     migration/5-35    [005] 369249.338554: funcgraph_exit:       # 881477.781 us |    }
     migration/5-35    [005] 369249.338554: funcgraph_exit:       # 881478.008 us |  }
     migration/5-35    [005] 369249.338554: funcgraph_entry:                   |  kthread_should_stop() {
     migration/5-35    [005] 369249.338554: funcgraph_exit:         0.023 us   |  }
     migration/5-35    [005] 369249.338554: funcgraph_entry:                   |  kthread_should_park() {
     migration/5-35    [005] 369249.338554: funcgraph_exit:         0.021 us   |  }
     migration/5-35    [005] 369249.338554: funcgraph_entry:                   |  cpu_stop_should_run() {
     migration/5-35    [005] 369249.338555: funcgraph_entry:                   |    _raw_spin_lock_irqsave() {
     migration/5-35    [005] 369249.338555: funcgraph_exit:         0.027 us   |    }
     migration/5-35    [005] 369249.338555: funcgraph_entry:                   |    _raw_spin_unlock_irqrestore() {
     migration/5-35    [005] 369249.338555: funcgraph_exit:         0.029 us   |    }
     migration/5-35    [005] 369249.338555: funcgraph_exit:         0.480 us   |  }
     migration/5-35    [005] 369249.338555: funcgraph_entry:                   |  cpu_stopper_thread() {
     migration/5-35    [005] 369249.338555: funcgraph_entry:                   |    _raw_qspin_lock_irq() {
     migration/5-35    [005] 369249.338555: funcgraph_exit:         0.023 us   |    }
     migration/5-35    [005] 369249.338556: funcgraph_entry:                   |    synchronize_sched_expedited_cpu_stop() {
     migration/5-35    [005] 369249.338556: funcgraph_exit:         0.032 us   |    }
     migration/5-35    [005] 369249.338556: funcgraph_entry:                   |    cpu_stop_signal_done() {
     migration/5-35    [005] 369249.338556: funcgraph_exit:         0.060 us   |    }
     migration/5-35    [005] 369249.338556: funcgraph_entry:                   |    _raw_qspin_lock_irq() {
     migration/5-35    [005] 369249.338556: funcgraph_exit:         0.024 us   |    }
     migration/5-35    [005] 369249.338556: funcgraph_exit:         1.051 us   |  }
     migration/5-35    [005] 369249.338556: funcgraph_entry:                   |  kthread_should_stop() {
     migration/5-35    [005] 369249.338557: funcgraph_exit:         0.022 us   |  }
     migration/5-35    [005] 369249.338557: funcgraph_entry:                   |  kthread_should_park() {
     migration/5-35    [005] 369249.338557: funcgraph_exit:         0.023 us   |  }
     migration/5-35    [005] 369249.338557: funcgraph_entry:                   |  cpu_stop_should_run() {
     migration/5-35    [005] 369249.338557: funcgraph_entry:                   |    _raw_spin_lock_irqsave() {
     migration/5-35    [005] 369249.338557: funcgraph_exit:         0.024 us   |    }
     migration/5-35    [005] 369249.338557: funcgraph_entry:                   |    _raw_spin_unlock_irqrestore() {
     migration/5-35    [005] 369249.338557: funcgraph_exit:         0.026 us   |    }
     migration/5-35    [005] 369249.338557: funcgraph_exit:         0.482 us   |  }
     migration/5-35    [005] 369249.338558: funcgraph_entry:                   |  schedule() {
        ...

The only function that migration thread executes is synchronize_sched_expedited_cpu_stop().