[SPDK] spdk_nvme_ns_cmd_read returning -ENOMEM

Hello,

I have a system with 8 1GB hugepages configured at boot time split between 2 sockets. I reserve all 8 for spdk with 

        struct spdk_env_opts opts{};
        spdk_env_opts_init(&opts);
        opts.mem_size = 1024 * 8;

When I call spdk_nvme_ns_cmd_read I get -ENOMEM if my buffer (which I allocated with spdk_zmalloc) is too large. The call to spdk_zmalloc succeeds so the buffer is created. I don't understand what the buffer size would have to do with spdk_nvme_ns_cmd_read failing. Can anyone shed any light? I've looked though the code a bit and it looks like nvme_allocate_request must be failing but I don't understand why.

Thanks,

Trevor