On Mon, Dec 16, 2013 at 05:16:17PM +0000, Zoltan Kiss wrote:

On 13/12/13 15:44, Wei Liu wrote:

quoted

On Thu, Dec 12, 2013 at 11:48:16PM +0000, Zoltan Kiss wrote:

quoted

A malicious or buggy guest can leave its queue filled indefinitely, in which
case qdisc start to queue packets for that VIF. If those packets came from an
another guest, it can block its slots and prevent shutdown. To avoid that, we
make sure the queue is drained in every 10 seconds

Oh I see where the 10 second constraint in previous patch comes from.

Could you define a macro for this constant then use it everywhere.

Well, they are not entirely the same thing, but worth making them
the same. How about using "unmap_timeout >
(rx_drain_timeout_msecs/1000)" in xenvif_free()? Then netback won't
complain about a stucked page if an another guest is permitted to
hold on to it.

Thanks for clarification. I see the difference. If they are not the same
by definition then we need to think more about making them the same in
practice.

If we use  "unmap_timeout > (rx_drain_timeout_msecs/1000)" then we
basically assume that guest RX path is the one who is most likely to
hold the packet for the longest time.

Wei.