1. A method comprising: receiving, with a memory buffer interface executing on a central processing unit (CPU), an instruction that includes information specifying whether an immediate mode should be enabled for a shared memory space of a memory, the shared memory space being accessible by the CPU and by a graphics processing unit (GPU) that includes a GPU cache that is configured to perform caching services for the shared memory space of the memory; and selectively enabling, with the memory buffer interface, the immediate mode for the shared memory space of the memory based on the information specifying whether the immediate mode should be enabled, wherein selectively enabling, with the memory buffer interface, the immediate mode comprises at least one of: causing the caching services performed by the GPU cache for the shared memory space of the memory to be disabled when the information specifying whether the immediate mode should be enabled specifies that the immediate mode should be enabled; and enabling a shared memory cache coherency mode for the GPU cache when the information specifying whether the immediate mode should be enabled specifies that the immediate mode should be enabled.