Hi, I've been giving the fast memory registration NFS RDMA patches a spin, and I've got a couple questions. AFAICS the default xprtrdma memory registration model is still RPCRDMA_ALLPHYSICAL; I had to "echo 6 > /proc/sys/sunrpc/rdma_memreg_strategy" prior to a mount to get fast registration. Given that fast registration has better security properties for iWARP, and the fallback is RPCRDMA_ALLPHYSICAL if fast registration is not supported, is it more appropriate to have RPCRDMA_FASTREG be the default? Second, it seems that the number of pages in a client fast memory registration is still limited to RPCRDMA_MAX_DATA_SEGS. So on a client write, without fast registration I get RPCRDMA_MAX_DATA_SEGS RDMA reads of 1 page each, whereas with fast registration I get 1 RDMA read of RPCRDMA_MAX_DATA_SEGS pages. In either case my maximum rsize, wsize for an RDMA mount is still 32 KiB. My understanding is that, e.g., a Chelsio T3 with the 2.6.27-rc driver can support 24 pages in a fast registration request. So, what I was hoping to see with a T3 were RPCs with RPCRDMA_MAX_DATA_SEGS chunks, each for a fast registration of 24 pages each, making possible an RDMA mount with 768 KiB for rsize, wsize. Is something like that possible? If so, do you have any work in progress along those lines? -- Jim -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
