A method for communication includes allocating in a memory of a host device a contiguous, cyclical set of buffers for use by a transport service instance on a network interface controller (NIC). First and second indices point respectively to a first buffer in the set to which the NIC is to write and a second buffer in the set from which a client process running on the host device is to read. Upon receiving at the NIC a message directed to the transport service instance and containing data to be pushed to the memory, the data are written to the first buffer that is pointed to by the first index, and the first index is advanced cyclically through the set. The second index is advanced cyclically through the set when the data in the second buffer have been read by the client process.