Processor, multiprocessor system, and method for causing memory managing apparatus to manage shared memory

A memory managing apparatus manages a memory shared by processors. The apparatus includes an allocator, an updater and a releaser. The allocator secures a memory area in the memory allocated to each processor based on a request of each processor and registers reference counters corresponding one-to-one to the processors. The updater adds 1 to a value of the reference counter corresponding to the processor managing the memory area when the memory area is allocated to each processor and subtracts 1 from the value of the reference counter corresponding to the processor managing the memory area when the memory area is released from the processor to which the memory area is allocated. The releaser releases the memory area from the processor to which the memory area is allocated when a sum of the values of the reference counters in the memory area updated by the updater is 0.