RE: [PATCH rdma-core 0/5] Common systemd/udev based boot support

Steve Wise
2017-07-28T16:08:36Z

>
> On Fri, Jul 28, 2017 at 08:51:28AM -0500, Steve Wise wrote:
>
> > Bringing down the NIC interfaces doesn't totally stop the adapter nor
destroy
> > the queues needed for RDMA. It does bring the links down on the ethernet
> > interfaces though. So it behaves like I thought. I tested this by running
an
> > rping, and while it was pushing rdma traffic, I did 'ifconfig ethX 0.0.0.0
down'
> > on the interface in use. The data flow stopped (and the iWARP/TCP stack
started
> > retransmitting). I then brought the link back up, and after a few seconds
the
> > rping traffic continued on.
>
> So, why defer creating queues until the first ifup?
>
> I can understand a nic driver that frees all memory when down (that is
> fairly common), but this arrangement seems really strange..

Maybe I'm mistaken about the need to wait for ifup to register the ULDs. I do
see the same queues are actually available after cxgb4 loads and before an ifup.
So maybe I can change the uld activation to earlier.