On Tue, Nov 27, 2012 at 04:56:30PM +0100, Frederic Weisbecker wrote: > 2012/11/27 Gleb Natapov <gleb@xxxxxxxxxx>: > > For KVM_PV_REASON_PAGE_NOT_PRESENT it behaves like an exception. > > Ok. > There seem to be a bug in kvm_async_pf_task_wait(). Using > idle_cpu(cpu) to find out if the current task is the idle task may not > work if there is pending wake up. Me may schedule another task but > when that other task sleeps later we can't schedule back to idle until > the fault is completed. > > The right way is to use is_idle_task(current) Agreed. But if you instead need to figure out whether or not RCU believes that the CPU is idle, use rcu_is_cpu_idle(). You need to figure out whether or not RCU believes that the CPU is idle if you are trying to play fast and loose with rcu_irq_enter() and rcu_irq_exit(). Thanx, Paul -- To unsubscribe from this list: send the line "unsubscribe linux-next" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
