IV46157: NATIVE OOM ON AIX 64BIT PLATFORM WHEN COMPRESSED REFERENCES ENAB LED

APAR status

• Closed as program error.

Error description

• Error Message: The JVM failed with Native OOM exception on AIX
  64bit platform when -Xcompressedrefs enabled.
  .
  To verify the NOOM is caused by this issue, confirm that the
  javacore reports 'native memory exhaustion', then run `dbx
  ${PATH_TO_JAVA} ${PATH_TO_core.dmp}`, run the `coremap` command,
  and verify that most memory segments under 0x100000000 only
  occupy 8MB. For example:
  
  (dbx) coremap
  ...
  Mapping: Shared Memory (size=0x800000)
     from (address): 0x50000000 - 0x50800000
  Mapping: Shared Memory (size=0x800000)
     from (address): 0x60000000 - 0x60800000
  Mapping: Shared Memory (size=0x800000)
     from (address): 0x70000000 - 0x70800000
  Mapping: Shared Memory (size=0x800000)
     from (address): 0x80000000 - 0x80800000
  Mapping: Shared Memory (size=0x800000)
     from (address): 0x90000000 - 0x90800000
  Mapping: Shared Memory (size=0x800000)
     from (address): 0xa0000000 - 0xa0800000
  Mapping: Shared Memory (size=0x800000)
     from (address): 0xb0000000 - 0xb0800000
  Mapping: Shared Memory (size=0x800000)
     from (address): 0xc0000000 - 0xc0800000
  Mapping: Shared Memory (size=0x800000)
     from (address): 0xd0000000 - 0xd0800000
  Mapping: Shared Memory (size=0x800000)
     from (address): 0xe0000000 - 0xe0800000
  Mapping: Shared Memory (size=0x800000)
     from (address): 0xf0000000 - 0xf0800000
  
  In this example, segments 0x5 through 0xf only show shared
  memory regions of size 0x800000 (8MB).
  
  If running dbx on a different system than where the core.dmp was
  produced, first run java/jre/bin/jextract, send the resulting
  zip to IBM support or the target system, unzip the file on the
  target system, and run `dbx -p /=./ ./${PATH_TO_JAVA}
  ./${PATH_TO_core.dmp}`. Note that this analysis may be possible
  even if the core dump is truncated and jextract/dbx report
  truncation warnings.
  

Local fix

• This issue can be worked around by disabling the compressed
  references by removing -Xcompressedrefs from the command line
  options or specifying -Xnocompressedrefs option at the end of
  the JVM options on the command line.
  

Problem summary

• The problem is caused when Xcompressedrefs enabled on AIX 64bit
  platform, JVM memory management routines did not take into
  account AIX Memory management limitations.
  

Problem conclusion

• This defect will be fixed in:
  6.0.1 SR7
  7.0.0 SR6
  6.0.0 SR15
  .
  The JVM has been updated to consider the AIX memory management
  limitations while allocating memory segments within the JVM.
  

Temporary fix

Comments

APAR Information

• 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

• R260 PSY

     UP

• R600 PSY

     UP