Excessive Kernel Memory Usage for ktune_tunable_a section

[maurige]

We have an HP-UX 11.31 system with 40Gb physical memory and I am surprised by the size required for ktune_tunable_a section (4GB).

This is the kmemusage output:

Physical memory       = 10451404   39.9g 100%

Free memory           =  1228942    4.7g  12%

User processes        =  5822223   22.2g  56%  details with -user

  Detached SHMEM      =       18   72.0k   0%  details with -shmem

System                =  3379445   12.9g  32%

  Kernel              =  2859781   10.9g  27%  kernel text and data

    Dynamic Arenas    =  1832740    7.0g  18%  details with -arena

      ktune_tunable_a =  1049587    4.0g  10%

      vx_global_kmcac =    65717  256.7m   1%

      spinlock_arena  =    65423  255.6m   1%

      misc region are =    59733  233.3m   1%

      reg_fixed_arena =    56642  221.3m   1%

      Other arenas    =   535638    2.0g   5%  details with -arena

    Super page pool   =   164771  643.6m   2%  details with -kas

    Emergency pool    =    21002   82.0m   0%  system critical reserve

    UAREA's           =    69968  273.3m   1%

    Overflow pte's    =    81720  319.2m   1%

    Static Tables     =   630826    2.4g   6%  details with -static

      pfdat           =   510322    1.9g   5%                                                                    

      vhpt            =    65536  256.0m   1%

      inode           =    29120  113.8m   0%

      text            =    10383   40.6m   0%  vmunix text section

      bss             =     6801   26.6m   0%  vmunix bss section

      Other tables    =     8664   33.8m   0%  details with -static

  File Cache          =   519664    2.0g   5%  details with -ufc

Using -arena option for kmemusage we get:

....

----------------------------------------------------------------------
Dynamic Arenas:

Variable arena "ktune_tunable_a" owns 1049587 pages (4.0gb):
Regular (Interleaved First) free lists account for 1049587 pages (4.0gb):
  Free objects represent 8.0kb (0%) of all memory in this arena.
  idx objsz   pages   bytes   %   nobjs    used    free   %
    1   248       1    4.0k   0      15       3      12  80
    3   504       1    4.0k   0       7       1       6  86
    7  1272       1    4.0k   0       3       1       2  67
   15  4096       1    4.0k   0       1       1       0   0
   16  8192       2    8.0k   0       1       1       0   0
   17 12288       6   24.0k   0       2       2       0   0
   23    xl 1049575    4.0g 100      na

 ....

I would be great if someone can help me to identify what is the source of this memory usage and how I can reduce it.

Thanks a lot