On Tue, Jun 23, 2020 at 05:05:51PM +0530, Haris Iqbal wrote: > On Tue, Jun 23, 2020 at 7:54 PM Jason Gunthorpe <jgg@xxxxxxxx> wrote: > > > > On Tue, Jun 23, 2020 at 07:15:03PM +0530, Haris Iqbal wrote: > > > On Tue, Jun 23, 2020 at 5:47 PM Jason Gunthorpe <jgg@xxxxxxxx> wrote: > > > > > > > > On Tue, Jun 23, 2020 at 03:20:27PM +0530, Haris Iqbal wrote: > > > > > Hi Jason and Leon, > > > > > > > > > > Did you get a chance to look into my previous email? > > > > > > > > Was there a question? > > > > > > Multiple actually :) > > > > > > > > > > > Jason > > > > > > In response to your emails, > > > > > > > Somehow nvme-rdma works: > > > > > > I think that's because the callchain during the nvme_rdma_init_module > > > initialization stops at "nvmf_register_transport()". Here only the > > > "struct nvmf_transport_ops nvme_rdma_transport" is registered, which > > > contains the function "nvme_rdma_create_ctrl()". I tested this in my > > > local setup and during kernel boot, that's the extent of the > > > callchain. > > > The ".create_ctrl"; which now points to "nvme_rdma_create_ctrl()" is > > > called later from "nvmf_dev_write()". I am not sure when this is > > > called, probably when the "discover" happens from the client side or > > > during the server config. > > > > > > It seems that the "rdma_bind_addr()" is called by the nvme rdma > > > module; but during the following events > > > 1) When a discover happens from the client side. Call trace for that looks like, > > > [ 1098.409398] nvmf_dev_write > > > [ 1098.409403] nvmf_create_ctrl > > > [ 1098.414568] nvme_rdma_create_ctrl > > > [ 1098.415009] nvme_rdma_setup_ctrl > > > [ 1098.415010] nvme_rdma_configure_admin_queue > > > [ 1098.415010] nvme_rdma_alloc_queue > > > [ 1098.415032] rdma_resolve_addr > > > [ 1098.415032] cma_bind_addr > > > [ 1098.415033] rdma_bind_addr > > > > > > 2) When a connect happens from the client side. Call trace is the same > > > as above, plus "nvme_rdma_alloc_queue()" is called n number of times; > > > n being the number of IO queues being created. > > > > > > On the server side, when an nvmf port is enabled, that also triggers a > > > call to "rdma_bind_addr()", but that is not from the nvme rdma module. > > > may be nvme target rdma? (not sure). > > > > > > Does this make sense or am I missing something here? > > > > It make sense, delaying creating and CM ID's until user space starts > > will solve this init time problme > > Right, and the patch is trying to achieve the delay by changing the > init level to "late_initcall()" It should not be done with initcall levels > > Right rdma_create_id() must precede anything that has problems, and it > > should not be done from module_init. > > I understand this, but I am not sure why that is; as in why it should > not be done from module_init? Because that is how our module ordering scheme works > > It is not OK to create RDMA CM IDs outside > > a client - CM IDs are supposed to be cleaned up when the client is > > removed. > > > > Similarly they are supposed to be created from the client attachment. > > This again is a little confusing to me, since what I've observed in > nvmt is, when a server port is created, the "rdma_bind_addr()" > function is called. > And this goes well with the server/target and client/initiator model, > where the server has to get ready and start listening before a client > can initiate a connection. > What am I missing here? client means a struct ib_client Jason > > > > > Jason >
