Method and system for efficient memory region deallocation

A system, comprising:

• a host executing a software application, wherein the software application is configured to issue a first invalidation command and a second invalidation command to deallocate a memory region in the host, wherein the first invalidation command is for invalidating at least one key for access to the memory region, and the second invalidation command is for invalidating a translation lookaside buffer (TLB) entry for the memory region;
• and
• a host communication adapter (HCA) operatively connected to the host and configured to:
• receive the first and second invalidation commands;
• invalidate the at least one key associated with the memory region;
• determine whether all memory access requests to the memory region have been processed by the HCA;
• stall processing of the second invalidation command, when outstanding memory access requests to the memory region are present;
• and
• process the outstanding memory access requests for the memory region before executing the second invalidation command invalidating the TLB entry for the memory region.

A host channel adapter (HCA) comprising:

• a direct memory access (DMA) validation module for storing a DMA validation table and a plurality of memory access keys, each of which is a credential to authenticate a memory access request, wherein the DMA validation module is configured to:
• authenticate the memory access request using a corresponding key;
• and
• process a command to invalidate a memory access key by invalidating a corresponding DMA validation entry in the DMA validation table;
• and
• a memory management module (MMU) for storing a translation lookaside buffer (TLB) comprising a plurality of memory address translations for a plurality of memory regions,
• wherein the HCA is configured to:
• receive and process a request to deallocate a memory region of the plurality of memory regions, wherein the request to deallocate the memory region comprises a first invalidation command for invalidating at least one key associated with the memory region and a second invalidation command for invalidating a translation lookaside buffer (TLB) entry for the memory region;
• invalidate at least one key associated with the memory region;
• determine whether all memory access requests to the memory region have completed address translation in the MMU;
• stall processing of the second invalidation command, when outstanding memory access requests to the memory region are present;
• and
• process the outstanding memory access requests for the memory region before executing the second invalidation command.