On Sun, Mar 21, 2010 at 12:11:33PM +0200, Avi Kivity wrote: > On 03/21/2010 11:55 AM, Michael S. Tsirkin wrote: > >On Fri, Mar 19, 2010 at 03:19:27PM -0700, Sridhar Samudrala wrote: > >>When creating a guest with 2 virtio-net interfaces, i am running > >>into a issue causing the 2nd i/f falling back to userpace virtio > >>even when vhost is enabled. > >> > >>After some debugging, it turned out that KVM_IOEVENTFD ioctl() > >>call in qemu is failing with ENOSPC. > >>This is because of the NR_IOBUS_DEVS(6) limit in kvm_io_bus_register_dev() > >>routine in the host kernel. > >> > >>I think we need to increase this limit if we want to support multiple > >>network interfaces using vhost-net. > >>Is there an alternate solution? > >> > >>Thanks > >>Sridhar > >Nothing easy that I can see. Each device needs 2 of these. Avi, Gleb, > >any objections to increasing the limit to say 16? That would give us > >5 more devices to the limit of 6 per guest. > > Increase it to 200, then. > Currently on each device read/write we iterate over all registered devices. This is not scalable. > Is the limit visible to userspace? If not, we need to expose it. > > -- > error compiling committee.c: too many arguments to function -- Gleb. -- 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
