- nm_frame_nr must equal the actual number of frames as specified above.
-When the kernel can't allocate phsyically continuous memory for a ring block,
+When the kernel can't allocate physically continuous memory for a ring block,
it will fall back to use physically discontinuous memory. This might affect
performance negatively, in order to avoid this the nm_frame_size parameter
should be chosen to be as small as possible for the required frame size and