Computer and memory control method

A computer comprising:

• a first memory;
• a second memory that has an I/O speed lower than an I/O speed of the first memory;
• and
• a processor that is coupled to the first memory, the second memory, and a storage device, wherein
• the first memory has a work area and a first cache area where data input to and output from the storage device is temporarily stored,
• the second memory has a second cache area where the data input to and output from the storage device is temporarily stored and a swap area to be a saving destination of data stored in the work area, and
• when an input/output amount to be an amount of data input to and output from the storage device is larger than a predetermined input/output amount, the processor is configured to execute a first cache area expansion process for reducing the work area and expanding the first cache area.