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 <a href="https://bugs.openjdk.java.net/browse/JDK-8171181">parent JEP</a>.

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.

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

Specification

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