PK94490: 32BIT USERSPACE APPLICATIONS NEED TO BE COMPILED WITH THE -BMAXD ATA OPTION TO INCREASE THE MAXIMUM SIZE OF DATA SEGMENT/HEAP

APAR status

• Closed as program error.

Error description

• IBM Rational ClearCase (TM) 32bit UserSpace applications on IBM
  AIX (TM) need to be compiled with the -bmaxdata option to increa
  se the maximum size of data segment or heap.
  
  
  
  
  
  
  ClearCase 7.0.0.0, 7.0.1, 7.1
     ALL binary executables
  
  MultiSite 7.0
     Most bianry executables  -?  IC52682 repaired some
  
  
  
  AIX - ALL
  
  
  
  
  
  Symptoms:
  
  
  
  ClearCase and MultiSite UserSpace processes are running on an AI
  X system with reserve memory available for all processes.  For i
  nstance, clearmake reads in a large Makefile, with hundreds of i
  ncludes and thousands of macros.
  
  While monitoring the system memory and
  noting that the system has plenty of physical memory while clear
  make is running, clearmake cores with the following in the backt
  race:
  
  
  
  948972:
  
  statx('/usr/intranet/clearcase/java/definitions/loader10001.t',
  
  0x2FF0F7B0, 128, 010) = 0
  
  948972: open('/usr/intranet/ clearcase
  
  /java/definitions/loader10001.t', O_RDONLY) = 10
  
  948972: kioctl(10, 22528, 0x00000000, 0x00000000) Err#25 ENOTTY
  
  948972: kwrite(1, 0xF04420D0, 89)   = 89
  
  948972: kioctl(10, 22528, 0x00000000, 0x00000000) Err#25 ENOTTY
  
  948972: kread(10, ' #   D O   N O T   E D I'.., 4096) = 992
  
  948972: __libc_sbrk(0x00000000)    Err#12 ENOMEM
  
  948972: __libc_sbrk(0x00000000)    = 0x2FEF9890
  
  948972: __libc_sbrk(0x00000000)    Err#12 ENOMEM
  
  948972: __libc_sbrk(0x00000000)    Err#12 ENOMEM
  
  948972: __libc_sbrk(0x00000000)    Err#12 ENOMEM
  
  948972: __libc_sbrk(0x00000000)    Err#12 ENOMEM
  
  
  
  
  
  As seen above, the system cannot allocate memory beyond ~256MB:
  
  0x2FF0F7B0
  
  
  
  In looking at the ulimit, the data(kbytes) is set to unlimited.
   Attempting to adjust the maxdata size of any executing applicat
  ion fails by setting the following environment variable has no a
  ffect (setting the maxdata value to 2GB = 8 256MB
  
  segments):
  
     export LRD_CNTRL=MAXDATA=0x80000000
  
  
  
  
  
  Cause:
  
  
  
  AIX applications, by default, have the maxdata value set to 256M
  B.  Unfortunately, in rare occasions, the ClearCase UserSpace ap
  plications may require more memory than is allowed by default.
  In such cases, the application must be compiled with the -bmaxda
  ta:0x80000000 option (2GB maximum, 8 256 segments).
  
  
  
  Because the system places user data and the user stack within a
  single segment, the system limits the maximum amount of stack an
  d data to slightly less than 256MB (as seen above in the
  
  sbrk() failure). This size is adequate for most applications:  H
  owever, certain applications require large initialized or uninit
  ialized data areas, and thus the data areas can be created
  
  dynamically with the malloc, brk or sbrk subroutine.
  
  
  
  LOCAL FIX:
  
  1) Compile the applications with the -bmaxdata:0x80000000 option
  
  
  
  2) Contact IBM Rational Support for a script to change the binar
  ies.
  

Local fix

Problem summary

• ClearCase  user space applications have the maxdata value set to
  256MB.  Unfortunately, in rare occasions, ClearCase user space
  applications may require more memory than is allowed by default.
  In such cases, the application will crash.
  

Problem conclusion

• A fix is available in ClearCase version 7.1.1
  

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

  CLEARCASE WIN

• Fixed component ID

  5724G2900

Applicable component levels

• R711 PSY

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