Linux Virtualization - May 2018 - Shepherd request (P83): Multipath TCP: Present Use Cases and an Upstream Future

On 5/22/2018 2:08 AM, Jiri Pirko wrote:
> Tue, May 22, 2018 at 11:06:37AM CEST, jiri at resnulli.us wrote:
>> Tue, May 22, 2018 at 04:06:18AM CEST, sridhar.samudrala at intel.com
wrote:
>>> Use the registration/notification framework supported by the
generic
>>> failover infrastructure.
>>>
>>> Signed-off-by: Sridhar Samudrala <sridhar.samudrala at
intel.com>
>> In previous patchset versions, the common code did
>> netdev_rx_handler_register() and netdev_upper_dev_link() etc
>> (netvsc_vf_join()). Now, this is still done in netvsc. Why?
>>
>> This should be part of the common "failover" code.
Based on Stephen's feedback on earlier patches, i tried to minimize the
changes to
netvsc and only commonize the notifier and the main event handler routine.
Another complication is that netvsc does part of registration in a delayed
workqueue.

It should be possible to move some of the code from net_failover.c to generic
failover.c in future if Stephen is ok with it.

>>
> Also note that in the current patchset you use IFF_FAILOVER flag for
> master, yet for the slave you use IFF_SLAVE. That is wrong.
> IFF_FAILOVER_SLAVE should be used.
Not sure which code you are referring to.? I only set IFF_FAILOVER_SLAVE
in patch 3.

Tue, May 22, 2018 at 05:28:42PM CEST, sridhar.samudrala at intel.com
wrote:
>
>On 5/22/2018 2:08 AM, Jiri Pirko wrote:
>> Tue, May 22, 2018 at 11:06:37AM CEST, jiri at resnulli.us wrote:
>> > Tue, May 22, 2018 at 04:06:18AM CEST, sridhar.samudrala at
intel.com wrote:
>> > > Use the registration/notification framework supported by the
generic
>> > > failover infrastructure.
>> > > 
>> > > Signed-off-by: Sridhar Samudrala <sridhar.samudrala at
intel.com>
>> > In previous patchset versions, the common code did
>> > netdev_rx_handler_register() and netdev_upper_dev_link() etc
>> > (netvsc_vf_join()). Now, this is still done in netvsc. Why?
>> > 
>> > This should be part of the common "failover" code.
>
>Based on Stephen's feedback on earlier patches, i tried to minimize the
changes to
>netvsc and only commonize the notifier and the main event handler routine.
>Another complication is that netvsc does part of registration in a delayed
workqueue.
:( This kind of degrades the whole efford of having single solution
in "failover" module. I think that common parts, as
netdev_rx_handler_register() and others certainly is should be inside
the common module. This is not a good time to minimize changes. Let's do
the thing properly and fix the netvsc mess now.

>
>It should be possible to move some of the code from net_failover.c to
generic
>failover.c in future if Stephen is ok with it.
>
>
>> > 
>> Also note that in the current patchset you use IFF_FAILOVER flag for
>> master, yet for the slave you use IFF_SLAVE. That is wrong.
>> IFF_FAILOVER_SLAVE should be used.
>
>Not sure which code you are referring to.? I only set IFF_FAILOVER_SLAVE
>in patch 3.
The existing netvsc driver.

On Tue, May 22, 2018 at 05:36:14PM +0200, Jiri Pirko
wrote:
> Tue, May 22, 2018 at 05:28:42PM CEST, sridhar.samudrala at intel.com wrote:
> >
> >On 5/22/2018 2:08 AM, Jiri Pirko wrote:
> >> Tue, May 22, 2018 at 11:06:37AM CEST, jiri at resnulli.us wrote:
> >> > Tue, May 22, 2018 at 04:06:18AM CEST, sridhar.samudrala at
intel.com wrote:
> >> > > Use the registration/notification framework supported by
the generic
> >> > > failover infrastructure.
> >> > > 
> >> > > Signed-off-by: Sridhar Samudrala <sridhar.samudrala
at intel.com>
> >> > In previous patchset versions, the common code did
> >> > netdev_rx_handler_register() and netdev_upper_dev_link() etc
> >> > (netvsc_vf_join()). Now, this is still done in netvsc. Why?
> >> > 
> >> > This should be part of the common "failover" code.
> >
> >Based on Stephen's feedback on earlier patches, i tried to minimize
the changes to
> >netvsc and only commonize the notifier and the main event handler
routine.
> >Another complication is that netvsc does part of registration in a
delayed workqueue.
> 
> :( This kind of degrades the whole efford of having single solution
> in "failover" module. I think that common parts, as
> netdev_rx_handler_register() and others certainly is should be inside
> the common module. This is not a good time to minimize changes. Let's
do
> the thing properly and fix the netvsc mess now.
> 
> 
> >
> >It should be possible to move some of the code from net_failover.c to
generic
> >failover.c in future if Stephen is ok with it.
> >
> >
> >> > 
> >> Also note that in the current patchset you use IFF_FAILOVER flag
for
> >> master, yet for the slave you use IFF_SLAVE. That is wrong.
> >> IFF_FAILOVER_SLAVE should be used.
> >
> >Not sure which code you are referring to.? I only set
IFF_FAILOVER_SLAVE
> >in patch 3.
> 
> The existing netvsc driver.
We really can't change netvsc's flags now, even if it's interface is
messy, it's being used in the field. We can add a flag that makes netvsc
behave differently, and if this flag also allows enhanced functionality
userspace will gradually switch.

Anything breaking userspace I fully expect Stephen to nack and
IMO with good reason.

-- 
MST