On Mon, Oct 05, 2020 at 06:27:39PM +0800, Ka-Cheong Poon wrote: > On 10/2/20 10:04 PM, Jason Gunthorpe wrote: > > > that namespace to use it. If there are a large number of namespaces, > > > there won't be enough devices to assign to all of them (e.g. the > > > hardware I have access to only supports up to 24 VFs). The shared > > > mode can be used in this case. Could you please explain what needs > > > to be done to support a large number of namespaces in exclusive > > > mode? > > > > Modern HW supports many more than 24 VFs, this is the expected > > interface > > Do you have a ballpark on how many VFs are supported? Is it in > the range of many thousands? Yes > BTW, while the shared mode is still here, can there be a simple > way for a client to find out which mode the RDMA subsystem is using? Return NULL for the namespace > > The new cm_id starts with the same ->context as the listener, the ULP should > > use this to pass any data, such as the namespace. > > This is what I suspected as mentioned in the previous email. But > this makes it inconvenient if the context is already used for > something else. Don't see why. the context should be allocated memory, so the ULP can put several things lin there. > > I'm skeptical ULPs should be doing per-ns stuff like that. A ns aware > > ULP should fundamentally be linked to some FD and the ns to use should > > derived from the process that FD is linked to. Keeping per-ns stuff > > seems wrong. > > > It is a kernel module. Which FD are you referring to? It is > unclear why a kernel module must associate itself with a user > space FD. Is there a particular reason that rdma_create_id() > needs to behave differently than sock_create_kern() in this > regard? Somehow the kernel module has to be commanded to use this namespace, and generally I expect that command to be connected to FD. We don't have many use cases where the kernel operates namespaces independently.. > While discussing about per namespace stuff, what is the reason > that the cma_wq is a global shared by all namespaces instead of > per namespace? Is there a problem to have a per namespace cma_wq? Why would we want to do that? Jason
