[ovs-dev] [PATCH] userspace-tso: Document the minimum kernel version.
fbl at sysclose.org
Tue Mar 10 14:41:54 UTC 2020
On Fri, Mar 06, 2020 at 04:50:38PM +0100, Ilya Maximets wrote:
> On 3/2/20 8:51 PM, Flavio Leitner wrote:
> > On Mon, Mar 02, 2020 at 01:11:35PM +0100, Ilya Maximets wrote:
> >> On 2/28/20 11:58 PM, Flavio Leitner wrote:
> >>> The kernel needs to be at least 4.19-rc7 to include the commit
> >>> 9d2f67e43b73 ("net/packet: fix packet drop as of virtio gso")
> >>> otherwise the TSO packets are dropped when using raw sockets.
> >>> Fixes: 29cf9c1b3b9c ("userspace: Add TCP Segmentation Offload support")
> >>> Reported-by: Yi Yang (杨燚)-云服务集团 <yangyi01 at inspur.com>
> >>> Signed-off-by: Flavio Leitner <fbl at sysclose.org>
> >>> ---
> >>> Documentation/topics/userspace-tso.rst | 4 ++++
> >>> 1 file changed, 4 insertions(+)
> >>> This applies to branch-2.13 as well.
> >>> diff --git a/Documentation/topics/userspace-tso.rst b/Documentation/topics/userspace-tso.rst
> >>> index 0fbac93a5..da370e64f 100644
> >>> --- a/Documentation/topics/userspace-tso.rst
> >>> +++ b/Documentation/topics/userspace-tso.rst
> >>> @@ -113,6 +113,10 @@ __ https://patches.dpdk.org/patch/64136/
> >>> This fix is expected to be included in the 19.11.1 release. When OVS migrates
> >>> to this DPDK release, this limitation can be removed.
> >>> +All kernel devices that use the raw socket interface (veth, for example)
> >>> +require a kernel with minimum version of 4.19-rc7 to include the commit:
> >>> +9d2f67e43b73 ("net/packet: fix packet drop as of virtio gso").
> >> I'm not very happy with this kind of documentation updates. The main reason
> >> is that every distribution uses their own custom kernel with some patches
> >> backported or not. In this particular case we seem to have issue with
> >> particular ubuntu kernel that happened to not have this bug fix backported.
> >> If someone uses non-lognterm upstream kernel that is out of its support
> >> lifetime it's his/her responsibility to backport bugfixes.
> >> Upstream LTS kernel 4.14 has this bugfix backported and there should be
> >> no issues. Upstream LTS 4.9 might not have this issue at all and work
> >> fine (I didn't check).
> >> What we can document is that particular kernel version from the Ubuntu 16.04
> >> distribution has an issue and should not be used along with userspace-tso.
> >> Ideally, someone should file a bug for ubuntu kernel maintainers, so they
> >> will backport relevant patch and update their kernel since it's still in a
> >> supported state. In this case we will have no need to document anything.
> >> What do you think?
> > I think worth for Ubuntu users to open a bug, so that this gets
> > solved.
> > But I think the documentation is still valid. Yi and I spent time
> > to find the root cause and it is something out of OvS control, so
> > the best we can do is document the requirement.
> > Maybe we can word it differently so that the kernel version becomes
> > less relevant. For example:
> > "All kernel devices that use the raw socket interface (veth, for example)
> > require the kernel commit 9d2f67e43b73 ("net/packet: fix packet drop
> > as of virtio gso") in order to work properly. This commit was merged
> > in upstream kernel 4.19-rc7, so make sure your kernel is either
> > newer or contains the backport."
> > How does that sound to you now?
> That sounds better. Thanks.
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