> On 8/12/20 6:16 PM, Stokes, Ian wrote: > >> From: Sivaprasad Tummala <sivaprasad.tumm...@intel.com> > >> > > > > Just a quick one here folks, I spotted this issue when testing the > > deprecation > notice patch for vhost zero copy. > > > > Siva had previously submitted an RFC patch to work around the issue in OVS > > as > it had not been decided at the time whether it should be resolved at the DPDK > or > the OVS layer. > > > > https://patchwork.ozlabs.org/project/openvswitch/patch/20200519114912. > > 66381-2-sivaprasad.tumm...@intel.com/ > > > > Since then it looks like the application layer was selected as the correct > > place > to make this change so I've resubmitted the patch with some minor changes. > > > > I figure it makes sense to have this patch in place first before applying > > the > deprecation notice (otherwise zero copy cannot be used anyway). > > > > Thoughts? > > Ugh... This feature is broken. > > As for now, I think it's ok to not ask for linear buffers, just because this > feature is > experimental and users are aware of possible issues. > i.e. guests should be trusted to not provide segmented buffers. > > I'd say let's apply this along with deprecation notice. Another option > is to just completely remove the feature right away without deprecation which > is > kind of not user friendly.
Agreed, it's broken, lets give the one release notice for 2.14 and then remove would be my thoughts. Applied to master and 2.14 Thanks Ian > > Acked-by: Ilya Maximets <i.maxim...@ovn.org> > > > > > Ian > > > >> As of DPDK 19.11, in order to use dequeue-zero-copy in DPDK Vhost > >> library, the application has to disable the linear buffer option. > >> Hence dequeue-zero-copy is not supported for vhost application that > >> requires > linear buffers. > >> > >> An alternative DPDK based approach to disable the linear buffers > >> within the vhost library itself was proposed in [1], however the > >> consensus was that application should be responsible for disabling linear > buffers. > >> > >> As such this patch disables linear buffers when zero-copy is enabled. > >> > >> [1] https://patches.dpdk.org/patch/67200/ > >> > >> Fixes: 127b6a6eea02 ("dpdk: Update to use DPDK 19.11.") > >> Signed-off-by: Sivaprasad Tummala <sivaprasad.tumm...@intel.com> > >> --- > >> lib/netdev-dpdk.c | 6 ++++++ > >> 1 file changed, 6 insertions(+) > >> > >> diff --git a/lib/netdev-dpdk.c b/lib/netdev-dpdk.c index > >> 44ebf96da..b940b1ac2 > >> 100644 > >> --- a/lib/netdev-dpdk.c > >> +++ b/lib/netdev-dpdk.c > >> @@ -5059,6 +5059,12 @@ netdev_dpdk_vhost_client_reconfigure(struct > >> netdev *netdev) > >> /* Enable zero copy flag, if requested */ > >> if (zc_enabled) { > >> vhost_flags |= RTE_VHOST_USER_DEQUEUE_ZERO_COPY; > >> + /* DPDK vHost library doesn't allow zero-copy with linear > >> buffers. > >> + * Hence disable Linear buffer. > >> + */ > >> + vhost_flags &= ~RTE_VHOST_USER_LINEARBUF_SUPPORT; > >> + VLOG_WARN("Zero copy enabled, disabling linear buffer" > >> + " check for vHost port %s", dev->up.name); > >> } > >> > >> /* Enable External Buffers if TCP Segmentation Offload is > >> enabled. */ > >> -- > >> 2.13.6 > >> > >> _______________________________________________ > >> dev mailing list > >> d...@openvswitch.org > >> https://mail.openvswitch.org/mailman/listinfo/ovs-dev _______________________________________________ dev mailing list d...@openvswitch.org https://mail.openvswitch.org/mailman/listinfo/ovs-dev