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IJ29253: ADD UNDOCUMENTED PARAMETER TO AVOID PAGE RESERVATION RELATED MMAP DEADLOCK

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APAR status

  • Closed as program error.

Error description

  • In cases which has small pagepool size and
large file system block size, GPFS may wait
for page reservation unnecessarily because
GPFS tends to reserve more pages than necessary.

Local fix

  • 



Problem summary


    

  • In cases which has small pagepool size and
large file system block size, GPFS may wait
for page reservation unnecessarily because
GPFS tends to reserve more pages than necessary.

    



Problem conclusion


    

  • Benefits of the solution:
Avoid page reservation related mmap deadlock

Work Around:
None

Problem trigger:
Workload which access a file both in
mmap and regular read/write method

Symptom:
Hang/Deadlock/Unresponsiveness/Long
Waiters

Platforms affected:
ALL Linux OS environments

Functional Area affected:
mmap

Customer Impact:
High Importance

    



Temporary fix


    

  • 



Comments


    

  • 



APAR Information




    

  • APAR number
    IJ29253
    • 

  • Reported component name
    SPEC SCALE STD
    • 

  • Reported component ID
    5737F33AP
    • 

  • Reported release
    510
    • 

  • Status
    CLOSED  PER
    • 

  • PE
    NoPE
    • 

  • HIPER
    NoHIPER
    • 

  • Special Attention
    NoSpecatt / Xsystem
    • 

  • Submitted date
    2020-11-16
    • 

  • Closed date
    2020-11-16
    • 

  • Last modified date
    2020-11-16
    • 





    

  • 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
    SPEC SCALE STD
    • 

  • Fixed component ID
    5737F33AP
    • 



Applicable component levels


    








      
              
                            

              

              [{"Business Unit":{"code":"BU058","label":"IBM Infrastructure w\/TPS"},"Product":{"code":"STXKQY","label":"IBM Spectrum Scale"},"Platform":[{"code":"PF025","label":"Platform Independent"}],"Version":"510","Line of Business":{"code":"LOB26","label":"Storage"}}]
              

                                                                    

          
 
        

      

    

      

        

          

            
Document Information


            

            


                        

            Modified date:
            

            14 December 2020
            

            
                      

        


        

        


      

    

  



    

  

  
    
            

          
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