找出哪个进程正在使用共享内存

Question

I wonder about the shared memory is currently using in the system so I run the command:

ipcs -m

------ Shared Memory Segments --------
key        shmid      owner      perms      bytes      nattch     status
0x50040150 2195456    user-owner  660        65648      2
0x00000000 2228225    user-owner  660        32768      1
0x00000000 2260994    user-owner  660        1052672    1
0x00000000 2293763    user-owner  660        57304      2
0x00000000 2326532    user-owner  660        98256      1
0x00000000 2359301    user-owner  660        53184      1
0x00000000 2392070    user-owner  660        98416      2
0x00000000 2424839    user-owner  660        98416      2
0x00000000 2457608    user-owner  660        672000     2
0x00000000 2490377    user-owner  660        672000     2
0x00000000 2523146    user-owner  660        672000     2
0x00000000 2555915    user-owner  660        672000     2
0x00000000 2588684    user-owner  660        672000     2
0x00000000 2621453    user-owner  660        672000     2
0x00000000 2654222    user-owner  660        672000     2
0x00000000 2686991    user-owner  660        672000     2
0x43040150 2719760    user-owner  660        304        1
0x00000000 2752529    user-owner  660        32768      1
0x00000000 2785298    user-owner  660        266240     1
0x00000000 2818067    user-owner  660        49104      1
0x00000000 2850836    user-owner  660        167920     2
0x00000000 2883605    user-owner  660        102384     2
0x013352ab 720918     user-owner  666        4096       2

and then run cat /proc/meminfo |grep -i

cat /proc/meminfo |grep -i shmem<br/>
Shmem:             21592 kB 

as I see, there is a gap between the total shared memory in ipcs -m, which i could not understand which process is using could you help me on this?

Thank you

Answer 1

shmem includes more than ipc shared memory segments, for example things like a ramdisk.

/proc/pid/statm - third field indicates how much shared memory pages a process has. Example code:

cd /proc
for i in `ls -d * | grep -v self`
do 
  if [[ -f $i/statm ]];then 
     echo -n "$i "; cat $i/statm | perl -lan -e 'print ($F[2] * 4096)'; 
  fi  
done | sort -nr -k2 | head

4096 is page size from getconf PAGESIZE

See https://lists.kernelnewbies.org/pipermail/kernelnewbies/2013-July/008628.html and https://access.redhat.com/solutions/406773 for more possibilities.