Memory Free up Failing on Solaris 8 - Off-topic

From: VIVEK_SHARMA <VIVEK_SHARMA_at_infosys.com>
Date: Sun, 02 Feb 2003 22:58:48 -0800
Message-ID: <F001.00541BA9.20030202225848@fatcity.com>

Hi

SITUATION - On a production APP Server having about 4000 Concurrent application processes , the memory allocated does NOT seem to be getting freed even though the application program is issuing the respective call to Free the memory .

Qs Any /etc/system parameters , OS patches which should help ?

Qs Is our approach of using the pmap command Correct ? else what Command to find the "Private" memory taken up by a process would be advisable ?

Qs How to find the Total Amount of Swap Consumed ?
[ We probably do NOT know how to interpret the vmstat output Correctly ,
top/swap -s commands show an output Differing greatly from df -k output for /tmp filesystem ]

Qs Any Body has encountered such as situation before ?

Configuration -
Solaris 2.8
Patch - Generic 108528-16 patch
Machine SF15K
CPUs = 36
RAM = 96 GB We created a Small Sample C program which allocates & FREEs memory but found that even after FREEing , the memory does NOT show as Freed in the pmap output . Is the following approach correct ?

DETAILS :-

@@@@@@@@@@@@@@@@@ SAMPLE C PROGRAM @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@

#include <stdio.h>
main()
{

        char *abc = NULL ;
        int     i = 0 ;
        for (i = 1; i < 10; i++){
                printf("allocating [%d] bytes\n", 10*1024*(i+1));
                abc = (char *)malloc(10*1024*(i+1));
                memset(abc, '\0', 10*1024*(i+1));
                getchar();

                free(abc);
                printf("Freeing [%d]\n", i);
                getchar();
        }
        exit() ;

}

@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@

RUN Output :-

STEP 1 - allocating [20480] bytes

pmap -x <PID of Above program process>

 Address   Kbytes Resident Shared Private Permissions       Mapped File
00010000       8       8       8       - read/exec         a.out
00020000       8       8       -       8 read/write/exec   a.out
00022000      24      24       -      24 read/write/exec     [ heap ]
FF280000     688     688     688       - read/exec         libc.so.1
FF33C000      32      32       -      32 read/write/exec   libc.so.1
FF370000      16      16      16       - read/exec         libc_psr.so.1
FF390000       8       8       8       - read/exec         libdl.so.1
FF3A0000       8       8       -       8 read/write/exec     [ anon ]
FF3B0000     152     152     152       - read/exec         ld.so.1
FF3E6000       8       8       -       8 read/write/exec   ld.so.1
FFBEC000      16      16       -      16 read/write/exec     [ stack ]
--------  ------  ------  ------  ------
total Kb     968     968     872      96

THE "Private" memory allocated by the [ heap ] is 24 K

STEP 2 - Freeing the memory allocated in the above Step

Freeing [1]

pmap -x <PID of Above program process>

 Address   Kbytes Resident Shared Private Permissions       Mapped File
00022000      24      24       -      24 read/write/exec     [ heap ]  

RESULT - THE "Private" memory allocated previously does NOT get Freed &
[ heap ] continues to be 24 K

STEP 3 -
allocating [30720] bytes

pmap -x <PID of Above Program process>

 Address   Kbytes Resident Shared Private Permissions       Mapped File
00022000      32      32       -      32 read/write/exec     [ heap ]

STEP 4 - Freeing the memory allocated in the above Step Freeing [2]

pmap -x <PID of Above program process>

 Address   Kbytes Resident Shared Private Permissions       Mapped File
00022000      32      32       -      32 read/write/exec     [ heap ]

RESULT - THE "Private" memory allocated previously in Step 3 does NOT get Freed &
[ heap ] continues to be 32 K

Thanks

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Author: VIVEK_SHARMA
  INET: VIVEK_SHARMA_at_infosys.com

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Received on Mon Feb 03 2003 - 00:58:48 CST