An example system comprises one or more processing nodes to execute one or more processes; a switching fabric coupled to the one or more processing nodes; a fabric-attached memory (FAM) coupled with the switching fabric; and a memory allocator to allocate and release memory in the FAM in response to memory allocation requests and memory release requests from the one or more processes. The memory allocator is to partition the FAM into a memory shelf comprising a plurality of memory books of equal size. The memory allocator is to map a shelf into a virtual memory zone, the zone aligned with the boundaries of one or more books. The memory allocator is to maintain an indexed free-memory list where each index level is an entry point to a list of free memory blocks of a particular size in the zone, and the memory allocator to maintain a bitmap of the zone to identify if a memory block of a particular size is allocated.