Messages in this thread |  | | Date | Mon, 16 Dec 2013 19:03:06 +0000 | From | Wei Liu <> | Subject | Re: [PATCH net-next v2 8/9] xen-netback: Timeout packets in RX path |
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On Mon, Dec 16, 2013 at 05:16:17PM +0000, Zoltan Kiss wrote: > On 13/12/13 15:44, Wei Liu wrote: > >On Thu, Dec 12, 2013 at 11:48:16PM +0000, Zoltan Kiss wrote: > >>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.
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