Methods and apparatus for buffer allocation and memory management are described. A plurality of buffers of a memory may be allocated, by a memory controller, with the buffers having variable sizes. The memory controller may maintain a mapping table that associates each of a plurality of access keys to a respective one of a plurality of page addresses of a plurality of pages of the memory. Each of the buffers may respectively include one or more contiguous pages of the plurality of pages of the memory. Each page of the plurality of pages may include one or more blocks of the memory. The mapping table may include one or more entries organized in a tree structure.