IV09725: JVM FAILS TO DECOMMIT 'SHMGET' ALLOCATED MEMORY DURING HEAP SHRI NKING ON AIX

APAR status

• Closed as program error.

Error description

• Error Message: N/A
  .
  Stack Trace: N/A
  .
  In AIX with Java6 , heap shrinking does not lead to memory being
  disclaimed.
  

Local fix

• Running with JVM option -Xlp4K
  

Problem summary

• In AIX with Java6 , heap shrinking does not lead to memory being
  disclaimed. The reason for this are as follows
  1) in Java6, page size defaults to 64k
  2) due to point (1), JVM uses the AIX call "shmget" to allocate
  memory
  3) present JVM design did not allow for disclaiming memory
  allocated through the "shmget" call.
  

Problem conclusion

• This defect will be fixed in:
  7.0.0 SR1
  6.0.1 SR1
  6.0.0 SR11
  .
  The JVM has been changed to disclaim/decommit "shmget" allocated
  memory.
  .
  To obtain the fix:
  Install build 20111108 or later
  

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