(z/OS® only)

When compressed references are used with a 64-bit OpenJ9 VM on z/OS®, this option forces the VM to use 31-bit memory allocation functions provided by z/OS.


Setting Effect Default
-XXnosuballoc32bitmem Enable
No setting Disable yes


This option is provided as a workaround for customers who need to use fewer pages of 31-bit virtual storage per VM invocation. Using this option might result in a small increase in the number of frames of central storage used by the VM. However, the option frees 31-bit pages for use by native code or other applications in the same address space.

If this option is not specified, the VM uses an allocation strategy for 31-bit memory that reserves a region of 31-bit virtual memory.