On Mon, 8 Jul 2019 06:37:14 +0000
Matan Azrad <ma...@mellanox.com> wrote:
> Hi Stephen
>
> From: Stephen Hemminger
> > Sent: Sunday, July 7, 2019 7:47 PM
> > To: Matan Azrad <ma...@mellanox.com>
> > Cc: anatoly.bura...@intel.com; dev@dpdk.org; Stephen Hemminger
> > <sthem...@microsoft.com>
> > Subject: Re: [dpdk-dev] [PATCH v2] examples/client_server_mp: check port
> > ownership
> >
> > On Sun, 7 Jul 2019 05:44:55 +0000
> > Matan Azrad <ma...@mellanox.com> wrote:
> >
> > > > + for (count = 0; pm != 0; pm >>= 1, ++count) {
> > > > + struct rte_eth_dev_owner owner;
> > > > +
> > > > + if ((pm & 0x1) == 0)
> > > > + continue;
> > > > +
> > > > + if (count >= max_ports) {
> > > > + printf("WARNING: requested port %u not present -
> > > > ignoring\n",
> > > > + count);
> > > > + continue;
> > > > + }
> > > > + if (rte_eth_dev_owner_get(count, &owner) < 0) {
> > > > + printf("ERROR: can not find port %u owner\n",
> > > > count);
> > >
> > > What if some entity will take ownership later?
> > > If you want the app will be ownership aware:
> > > if you sure that you want this port to be owned by this application
> > you need to take ownership on it.
> > > else:
> > > the port is hidden by RTE_ETH_FOREACH_DEV if it is owned by some entity.
> > > see how it was done in testpmd function: port_id_is_invalid().
> >
> > There are no mysterious entities in DPDK.
> > The only thing that can happen later is hotplug, and that will not change
> > state
> > of existing port.
> > This model is used for all applications. The application does not take
> > ownership, only device drivers do.
>
> A long discussions were done on it.
> There is an application model to take ownership as I wrote you above.
> You chose in the second option - not to be ownership aware.
>
> From docs:
> "10.4.2. Port Ownership
> The Ethernet devices ports can be owned by a single DPDK entity (application,
> library, PMD, process, etc). The ownership mechanism is controlled by ethdev
> APIs and allows to set/remove/get a port owner by DPDK entities. Allowing
> this should prevent any multiple management of Ethernet port by different
> entities.
>
> Note
>
> It is the DPDK entity responsibility to set the port owner before using it
> and to manage the port usage synchronization between different threads or
> processes."
>
> > The whole portmask as command-line parameter is a bad user experience
> > now, but that is a different problem.
>
> I think, this is the problem you should solve here.
No other application is doing this: testpmd, l3fwd, ... why do you think
this application is different. Plus you would be putting a new requirement on
all the user applications. That would be a user hostile change.
