How to Determine Shared Memory Usage within Solaris

To show system-wide shared memory allocations, use the following command:

# ipcs -ma

T        ID    KEY    MODE      OWNER  GROUP CREATOR CGROUP NATTCH SEGSZ  CPID   LPID    ATIME    DTIME    CTIME Shared Memory: m 754974778 0x3bd6 –rw——- ###### ######  ###### ######      1 64528 16056  16056 14:10:07 no-entry 14:10:07

This displays how much System V shared memory has been allocated, along with the attributes of those shared memory segments.  The SEGSZ column shows the sizes of any allocated segments in bytes.  The NATTCH column shows how many processes have attached to the shared memory segments, via calls to shmat(2).

Information relating to shared memory usage by individual processes is available from pmap(1), when executed with the -x option.  The LPID column in the ipcs(1) output above reports the ID of the last process that attached to or detached from this shared memory segment.  Looking at this process using pmap(1) shows that it is still attached to the above shared memory segment (0x2d00003a is 754974778 in decimal).

# pmap -x 16056 16056: /opt/firefox/plugin-container Address    Kbytes RSS Anon Locked Mode Mapped File … F75D0000       64   8    –      – rwxs- [ shmid=0x2d00003a ]