-Xmo / -Xmoi / -Xmos / -Xmox

Sets the size and behavior of the old (tenure) heap when using -Xgcpolicy:gencon.

You can use the -verbose:sizes option to find out the values that the VM is currently using.


Setting Effect Default
-Xmo<size> Equivalent to setting both -Xmos and -Xmox not set
-Xmoi<size> Set increment size of old (tenure) heap See Note
-Xmos<size> Set initial size of old (tenure) heap 75% of -Xms
-Xmox<size> Set maximum size of old (tenure) heap Same as -Xmx

Note: By default, the increment size (-Xmoi) is calculated on the expansion size, set by -Xmine and -Xminf. If you set -Xmoi to zero, no expansion is allowed.

See Using -X command-line options for more information about the <size> parameter.

Restriction: If you try to set -Xmo with either -Xmos or -Xmox, the VM does not start, returning an error.