Re: [PATCH V3 5/6] RDMA CM: Save Owning PID

Nir Muchtar
2010-12-21T15:05:50Z

On Mon, 2010-12-20 at 14:54 -0700, Jason Gunthorpe wrote:
> On Sun, Dec 19, 2010 at 04:36:22PM +0200, Nir Muchtar wrote:
> > On Tue, 2010-12-14 at 11:34 -0700, Jason Gunthorpe wrote:
> > > On Mon, Dec 13, 2010 at 06:22:49PM +0200, Nir Muchtar wrote:
> > > > Save owning PID to id-priv when creating id's/accepting connections.
> > >
> > > This should be called creator_pid, not owner - to avoid confusion.
>
> > But it's meant to be the owner and not necessarily the creator.
> > That's why its value is replaced in rdma_accept.
>
> There is no such thing as a single owner for a fd based resource
> like a RDMA_CM ID. The FD can be held by multiple processes. This is
> why the best you can do by storing PIDs at certain times is to
> constuct a creator_pid.
>
> Owner pid can only be determined by cross-referencing the inode of the
> FD that holds the ownership of the object to the processes that hold
> that FD.
>
> Jason

But an RDMA CM ID is not a FD based resource. An event channel is, but I
want to export ID stats and not event channel stats.
Are you saying that there's a scenario in which an RDMA CM ID is shared
between multiple processes?
Even if there is such a scenario, I think that by taking the PID of the
one that calls rdma_accept, the idea of an owner stays consistent.
I don't mind the name btw, just tying it to something else, which isn't
necessarily related.

Nir