[ovs-dev] [PATCH v2 1/1] DPDK: Remove support for vhost-user zero-copy.

[Kevin Traynor]

On 29/09/2020 17:44, Ilya Maximets wrote:
> On 9/29/20 6:33 PM, Stokes, Ian wrote:
>>> On 9/10/20 7:30 PM, Ian Stokes wrote:
>>>> Support for vhost-user dequeue zero-copy was deprecated in OVS 2.14
>>> with
>>>> the aim of removing it for OVS 2.15.
>>>>
>>>> OVS only supports zero copy for vhost client mode, as such it will cease
>>>> to function due to DPDK commit [1]
>>>>
>>>> Also DPDK is set to remove zero-copy functionality in DPDK 20.11 as
>>>> referenced by commit [2]
>>>>
>>>> As such remove support from OVS.
>>>>
>>>> [1] 715070ea10e6 ("vhost: prevent zero-copy with incompatible client
>>> mode")
>>>> [2] d21003c9dafa ("doc: announce removal of vhost zero-copy dequeue")
>>>>
>>>> Signed-off-by: Ian Stokes <ian.stokes at intel.com>
>>>>
>>>> ---
>>>> v1 -> v2
>>>> * Remove reference to zero copy in vhost post copy documentation.
>>>> * Add DPDK commits that have influenced OVS decision to remove support
>>>>   for zero-copy.
>>>> * Correct NEWS to reference removal rather than deprecation of zc.
>>>> ---
>>>>  Documentation/topics/dpdk/vhost-user.rst | 76 --------------------------------
>>>>  NEWS                                     |  2 +
>>>>  lib/netdev-dpdk.c                        | 25 -----------
>>>>  vswitchd/vswitch.xml                     | 11 -----
>>>>  4 files changed, 2 insertions(+), 112 deletions(-)
>>>>
>>>> diff --git a/Documentation/topics/dpdk/vhost-user.rst
>>> b/Documentation/topics/dpdk/vhost-user.rst
>>>> index 4af738d11..3be8f8b5e 100644
>>>> --- a/Documentation/topics/dpdk/vhost-user.rst
>>>> +++ b/Documentation/topics/dpdk/vhost-user.rst
>>>> @@ -339,10 +339,6 @@ The default value is ``false``.
>>>>      migration recovery was fixed for post-copy in 3.0 and few additional bug
>>>>      fixes (like userfaulfd leak) was released in 3.0.1.
>>>>
>>>> -    DPDK Post-copy feature requires avoiding to populate the guest
>>> memory
>>>> -    (application must not call mlock* syscall). So enabling mlockall and
>>>> -    dequeue zero-copy features is mis-compatible with post-copy feature.
>>>
>>> The part about mlockall is still valid, only zero-copy related words should be
>>> removed, e.g. "So enabling mlockall is mis-compatible with post-copy
>>> feature."
>>
>> Apologies for the delay Ilya, I was on PTO the last few weeks, sure will make think change and apply with an ACK from yourself if that’s ok?
> 
> OK, sure.  With this change:
> Acked-by: Ilya Maximets <i.maximets at ovn.org>
> 

+1

Acked-by: Kevin Traynor <ktraynor at redhat.com>

>>
>> Regards
>> Ian
>>>
>>> Best regards, Ilya Maximets.
>