APAR status
Closed as program error.
Error description
Error Message: N/A . Stack Trace: N/A . The JVM allocates more memory for the object heap than expected. For example, a JVM launched with options "-Xnocompressedrefs -Xmx15360M-Xlp:objectheap:pagesize=2G,nonpageable" allocates a 18G heap. Shown in a javacore as follows: "+--Java Heap: 19,327,352,832 bytes / 1 allocation"
Local fix
Do not use 2GB large pages
Problem summary
It is normal behavior for the allocated size of the object heap to be rounded up to the physical page size. For example, an object heap allocation size of 15GB in 2GB pages is rounded to 16GB. When running the -Xnocompressedrefs JVM (either explicitly or when the object heap size is larger than supported by the compressedrefs JVM), regardless of the page size an extra page is added to the object heap size on z/OS and zLinux for performance reasons. On z/OS an extra 4/8 bytes are required for 31-bit/64-bit JVMs which may use an entire extra page of memory.
Problem conclusion
An extra page is only added to the object heap size when the page size is smaller than 1GB. No extra bytes are required on z/OS. . This APAR will be fixed in the following Java Releases: 8 SR5 (8.0.5.0) . Contact your IBM Product's Service Team for these Service Refreshes and Fix Packs. For those running stand-alone, information about the available Service Refreshes and Fix Packs can be found at: https://www.ibm.com/developerworks/java/jdk/
Temporary fix
Comments
APAR Information
APAR number
IV96569
Reported component name
J9 COMMON CODE
Reported component ID
620700127
Reported release
270
Status
CLOSED PER
PE
NoPE
HIPER
NoHIPER
Special Attention
NoSpecatt / Xsystem
Submitted date
2017-05-24
Closed date
2017-05-24
Last modified date
2017-05-24
APAR is sysrouted FROM one or more of the following:
APAR is sysrouted TO one or more of the following:
Fix information
Fixed component name
J9 COMMON CODE
Fixed component ID
620700127
Applicable component levels
R270 PSY
UP
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Document Information
Modified date:
21 February 2022