On 22/06/2017 13:22, root wrote: > ============================================================== > > +poll_grow: (X86 only) > + > +This parameter is multiplied in the grow_poll_ns() to increase the poll time. > +By default, the values is 2. > + > +============================================================== > +poll_shrink: (X86 only) > + > +This parameter is divided in the shrink_poll_ns() to reduce the poll time. > +By default, the values is 2. Even before starting the debate on whether this is a good idea or a bad idea, KVM reduces the polling value to the minimum (10 us) by default when polling fails. Also, it shouldn't be bound to CONFIG_HYPERVISOR_GUEST, since there's nothing specific to virtual machines here. Regarding the good/bad idea part, KVM's polling is made much more acceptable by single_task_running(). At least you need to integrate it with paravirtualization. If the VM is scheduled out, you shrink the polling period. There is already vcpu_is_preempted for this, it is used by mutexes. Paolo
