Desired block size for persistent memory storage, for example, if a module has a table with 10 entries, each entry is size 64 bytes,
it can request 10 blocks with block size 64 bytes. On the other hand, the module can also request one block of size 640 based on how it would like to access or alter memory in persistent memory. First option is preferred when single entries that need to be updated often when having no impact on the other entries. While second option is preferred when entries of table are not changed on individually but have common point of loading and storing data.