On 28/10/2015 18:50, Yunhong Jiang wrote: > > No, I don't think you can use raw_spinlock there. The problem is not > > just eventfd_signal, it is especially wake_up_locked_poll. You cannot > > convert the whole workqueue infrastructure to use raw_spinlock. > > You mean the waitqueue, instead of workqueue, right? Yes. > One choice is to change > the eventfd to use simple wait queue, which is raw_spinlock. But use simple > waitqueue on eventfd may in fact impact real time latency if not in this > scenario. Userspace can put an arbitrary amount of tasks on the work queue, so it's not possible to use a simple wait queue. It would also touch multiple subsystems, so it's much better to bypass the eventfd completely. Paolo -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
