[ovs-dev] [PATCH] vswitchd: doc that tc-policy needs a restart

[Ilya Maximets]

On 1/29/21 11:33 PM, Marcelo Ricardo Leitner wrote:
> On Fri, Jan 29, 2021 at 10:31:46PM +0100, Ilya Maximets wrote:
>> On 12/23/20 2:01 PM, Marcelo Ricardo Leitner wrote:
>>> tc-policy, just like hw-offload, is protected by ovsthread_once_start()
>>> in netdev_set_flow_api_enabled() so lets document that changing it
>>> requires a restart in order for it to have effect.
>>>
>>> Signed-off-by: Marcelo Ricardo Leitner <marcelo.leitner at gmail.com>
>>> ---
>>>  vswitchd/vswitch.xml | 3 ++-
>>>  1 file changed, 2 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/vswitchd/vswitch.xml b/vswitchd/vswitch.xml
>>> index df5aa41a23da2622eee69f143a52a7e3b970488a..0b853ff26b76aebec8692ac1c59a54a7333e6330 100644
>>> --- a/vswitchd/vswitch.xml
>>> +++ b/vswitchd/vswitch.xml
>>> @@ -267,7 +267,8 @@
>>>            <ref column="other_config" key="hw-offload"/> is enabled.
>>>          </p>
>>>          <p>
>>> -          The default value is <code>none</code>.
>>> +          The default value is <code>none</code>. Changing this value requires
>>> +          restarting the daemon
>>
>> That is not fully correct.  Only disabling requires restart.
>> Changing the value from 'false' to 'true' is allowed in runtime.
> 
> I don't see where that is allowed. The only call I see to
> tc_set_policy() is from netdev_set_flow_api_enabled(), under the
> protection of ovsthread_once_start().

Yep.  But that call is inside the 'if':
  https://github.com/openvswitch/ovs/blob/master/lib/netdev-offload.c#L673

And this ovsthread_once_start() only executed if 'hw-offload' was set to
'true'.  This way you should be able to turn on offloading at any time,
but turning off requires restart.

> 
>>
>>>          </p>
>>>        </column>
>>>  
>>>
>>