Remote direct memory access in multi-tier memory systems

A method, comprising:

• connecting a first interface of a remote direct memory access network interface card to a memory bus;
• connecting a second interface of the remote direct memory access network interface card to a peripheral interconnect;
• connecting a third interface of the remote direct memory access network interface card to a computer network;
• receiving, in the remote direct memory access network interface card via the peripheral interconnect, a command;
• transferring, in response to the command, data between a remote apparatus connected to the computer network and a memory module configured on the memory bus, wherein the memory module includes a first memory and a second memory slower than the first memory;
• running, in the host system, a driver programmed for the remote direct memory access network interface card and configured to generate the command;
• wherein the remote direct memory access network interface card is configured to transfer the data of a virtual memory page between the remote apparatus and the second memory in the memory module.

A non-transitory computer storage medium storing instructions which, when executed by a computing system, cause the computing system to perform a method, the method comprising:

• generating a command to a remote direct memory access network interface card having:
• a first interface connected to a memory bus;
• a second interface connected to a peripheral interconnect;
• and a third interface connected to a computer network;
• before sending the command to the remote direct memory access network interface card to cause the remote direct memory access network interface card to transfer data of a virtual memory page between a remote apparatus connected to the computer network and a memory module configured on the memory bus:
• preventing the virtual memory page from being mapped to first memory of the memory module for duration of the remote direct memory access network interface card transferring the data between the remote apparatus and the memory module;
• and
• mapping the virtual memory page to a second memory of the memory module at last for the duration of the remote direct memory access network interface card transferring the data between the remote apparatus and the second memory in the memory module;
• and
• sending, via the peripheral interconnect to the remote direct memory access network interface card, the command.