Bug 1977850 - geneve virtual devices lack the NETIF_F_FRAGLIST feature
Summary: geneve virtual devices lack the NETIF_F_FRAGLIST feature
Keywords:
Status: CLOSED ERRATA
Alias: None
Product: Red Hat Enterprise Linux 8
Classification: Red Hat
Component: kernel
Version: 8.5
Hardware: Unspecified
OS: Unspecified
medium
medium
Target Milestone: beta
: ---
Assignee: Paolo Abeni
QA Contact: Jianlin Shi
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2021-06-30 15:23 UTC by Paolo Abeni
Modified: 2021-11-10 06:02 UTC (History)
5 users (show)

Fixed In Version: kernel-4.18.0-322.el8
Doc Type: If docs needed, set a value
Doc Text:
Clone Of:
Environment:
Last Closed: 2021-11-09 19:23:41 UTC
Type: Bug
Target Upstream Version:

Attachments (Terms of Use)


Links
System ID Private Priority Status Summary Last Updated
Gitlab redhat/rhel/src/kernel rhel-8 merge_requests 892 0 None None None 2021-06-30 15:35:47 UTC
Red Hat Product Errata RHSA-2021:4356 0 None None None 2021-11-09 19:24:26 UTC

Description Paolo Abeni 2021-06-30 15:23:21 UTC 
The mentioned device feature is not exposed by the geneve devices:

ethtool -k <geneve device name>|grep frag
	tx-scatter-gather-fraglist: off [fixed]

that leads to unneeded segmentation for GSO traffic traversing such device, impacting especially layered products like OSP.

Fixed by the upstream commit:

commit 18423e1a9d7d72c84f04e7f5fa31070855966ea7
Author: Xin Long <lucien.xin>
Date:   Fri Jan 15 17:47:46 2021 +0800

    geneve: add NETIF_F_FRAGLIST flag for dev features

With the above commit applied the expected result is:

ethtool -k <geneve device name>|grep frag
	tx-scatter-gather-fraglist: on
Comment 5 Jianlin Shi 2021-07-07 08:10:40 UTC 
reproduced on 4.18.0-316:

[root@hpe-dl380pgen8-02-vm-16 ~]# ip link add geneve1 type geneve id 1234 remote 1.1.1.1              
[root@hpe-dl380pgen8-02-vm-16 ~]# ethtool -k geneve1 | grep frag                                      
        tx-scatter-gather-fraglist: off [fixed]                                                       
[root@hpe-dl380pgen8-02-vm-16 ~]# uname -a                                                            
Linux hpe-dl380pgen8-02-vm-16.hpe2.lab.eng.bos.redhat.com 4.18.0-316.el8.x86_64 #1 SMP Mon Jun 21 15:32:48 EDT 2021 x86_64 x86_64 x86_64 GNU/Linux

Verified with kernel in comment 4:

[root@hpe-dl380pgen8-02-vm-16 ~]# uname -a
Linux hpe-dl380pgen8-02-vm-16.hpe2.lab.eng.bos.redhat.com 4.18.0-319.el8.mr892_210701_1056.x86_64 #1 SMP Thu Jul 1 11:09:06 UTC 2021 x86_64 x86_64 x86_64 GNU/Linux
[root@hpe-dl380pgen8-02-vm-16 ~]# ip link add geneve1 type geneve id 1234 remote 1.1.1.1              
[root@hpe-dl380pgen8-02-vm-16 ~]# ethtool  -k geneve1 | grep frag                                     
        tx-scatter-gather-fraglist: on
Comment 11 Jianlin Shi 2021-07-19 03:37:06 UTC 
Verified on 4.18.0-322:

[root@kvm-02-guest09 ~]# uname -a
Linux kvm-02-guest09.rhts.eng.brq.redhat.com 4.18.0-322.el8.x86_64 #1 SMP Wed Jul 7 22:22:31 EDT 2021 x86_64 x86_64 x86_64 GNU/Linux
[root@kvm-02-guest09 ~]# ip link add geneve1 type geneve id 1234 remote 1.1.1.1 
[root@kvm-02-guest09 ~]# ethtool -k geneve1 | grep frag
        tx-scatter-gather-fraglist: on
Comment 13 errata-xmlrpc 2021-11-09 19:23:41 UTC 
Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory (Moderate: kernel security, bug fix, and enhancement update), and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

https://access.redhat.com/errata/RHSA-2021:4356
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