Summary

Add a new flag -XX:AllocateHeapAt to support allocation of Java heap on an alternate memory device. (default: NULL)

Problem

Please refer to problem and motivation in the parent JEP.

Solution

The new flag provides a way for user to specify the backing memory to be used for Java heap allocation. This flag takes a directory path and Java VM, using memory mapping, can allocate Java heap on the device which is managed by the file system where the path resides.

1. This flag just changes where Java heap is allocated and does not affect behavior of Java application.
2. If the path specified does not exist or in case of other errors, the Java VM exits with relevant error message.
3. When this flag is not set, the behavior of Java VM is not affected.

Specification

product(ccstr, AllocateHeapAt, NULL, \
"Path to the directoy where a temporary file will be created " \
"to use as the backing store for Java Heap.")