Why 2GTO32G in the IARV64?
McKown, John
http://www-03.ibm.com/servers/enable/site/education/wp/1d71a/1d71a.pdf
<quote>
APAR OA26294 provides a direct assembler interface to z/OS Real Storage Manager (RSM), which allows memory allocations in the 2 GB (2^31) to 32 GB (2^35) virtual address range. The IBM JVM uses this API to allocate the Java heap in this virtual address range. It is noted that memory allocated using the RSM API can be backed by either 4 KB pages or large pages.
</quote>
Why 2^35 (32G)? Because that is the upper limit on Java's heap for using "compressed pointers". Above 32G of heap, Java does not compress pointers.
John McKown
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