On Thu, Feb 15, 2024 at 09:16:38AM +0100, Jakob Meng wrote: > On 30.01.24 10:44, Simon Horman wrote: > > On Fri, Jan 26, 2024 at 02:24:51PM +0100, [email protected] wrote: > >> From: Jakob Meng <[email protected]> > >> > >> In a scenario where OVN does load balancing and then SNAT with a OVS > >> userspace datapath [0], the recirc_depth may be greater than 6. In > >> that case, ovs-vswitchd might drop packets and raise warnings: > >> > >> dpif_netdev|WARN|Packet dropped. Max recirculation depth exceeded. > >> > >> Increasing MAX_RECIRC_DEPTH to 8 solves this issue. > >> > >> [0] > >> https://github.com/ovn-org/ovn/blob/dd5cd73e3df1bfb1a215cb45d1e2e03eff1d049a/tests/system-ovn-kmod.at#L740 > >> > >> Reported-at: https://issues.redhat.com/browse/FDP-251 > >> Signed-off-by: Jakob Meng <[email protected]> > > Hi Jakob, > > > > I'm unsure what the considerations were when setting this limit, > > but I do note that it was increased once before, from 5 to 6, > > for an OVN use-case [1]. So this approach seems reasonable to me. > > > > Acked-by: Simon Horman <[email protected]> > > > > [1] dpif-netdev: Set MAX_RECIRC_DEPTH to 6. > > https://github.com/openvswitch/ovs/commit/3f9d3836d63a > > > > Hi Ilya, > can we include this patch in 3.3, please? > > It is required for more complex setups like OKD/OpenShift with userspace > datapaths.
In the hope of moving this forwards: My feeling is that while on the one hand this is a wack-a-mole approach it does address a real problem in a well understood way, thus moving things in a positive direction. As for downside, there is a risk that this will blow the stack anyway or somehow cause resource exhaustion that didn't occur before. I didn't exercise the patch. But I do suspect that risk is minimal. And if it surfaces we will have to search for a better solution. But we don't have a better solution at this time - or at least I don't. So, other than what I assume is a small risk of regression, do we really lose anything by moving forward with this simple change at this time? _______________________________________________ dev mailing list [email protected] https://mail.openvswitch.org/mailman/listinfo/ovs-dev
