IPC Shared Memory Limit

IPC Shared Memory Limit

Post by Mark Vil » Mon, 06 Feb 1995 08:09:42

        I'm having trouble moving an IPC shm program from SunOS 4 to
SunOS 5. The important structure appears to be in /usr/include/sys/shm.h:
struct  shminfo {
        int     shmmax,         /* max shared memory segment size */
                shmmin,         /* min shared memory segment size */
                shmmni,         /* # of shared memory identifiers */
 -->            shmseg;         /* max attached shared memory     */
                                /* segments per process           */

shmseg (-->) was obsolete in SunOS 4, but Solaris seems to want to use
this, and it appears to be set to   7  (attaches/process).

        Any suggestions how I/my sysop can bump this to, say, 20?

Mark Villa                      

Meadowlands: 103.10.5/6         mine nor those of my organization."


IPC Shared Memory Limit

Post by Casper H.S. D » Tue, 07 Feb 1995 19:18:01

>shmseg (-->) was obsolete in SunOS 4, but Solaris seems to want to use
>this, and it appears to be set to   7  (attaches/process).
>    Any suggestions how I/my sysop can bump this to, say, 20?

Seting SysV IPC params is easy, just pick the param you
want to set and add it to /etc/system.  Then reboot.

The names of the parameters are:

set semsys:seminfo_semusz = <value>
set semsys:seminfo_semopm = <value>
set semsys:seminfo_semume = <value>
set semsys:seminfo_semaem = <value>
set semsys:seminfo_semmap = <value>
set semsys:seminfo_semvmx = <value>
set semsys:seminfo_semmsl = <value>
set semsys:seminfo_semmni = <value>
set semsys:seminfo_semmns = <value>
set semsys:seminfo_semmnu = <value>

set shmsys:shminfo_shmmin = <value>
set shmsys:shminfo_shmseg = <value>
set shmsys:shminfo_shmmax = <value>
set shmsys:shminfo_shmmni = <value>

set msgsys:msginfo_msgseg = <value>
set msgsys:msginfo_msgssz = <value>
set msgsys:msginfo_msgtql = <value>
set msgsys:msginfo_msgmap = <value>
set msgsys:msginfo_msgmax = <value>
set msgsys:msginfo_msgmnb = <value>
set msgsys:msginfo_msgmni = <value>


1. Shared Memory IPC

I'm working on a project that needs to use a shared memory
block for interprocess communication in Linux.  (I know there are
better ways for doing IPC, but this project specifically REQUIRES
shared memory.)  In particular, I'd like to be able to map memory
pages from process A into the memory space of process B.

I was thinking that the phys() mmap() functions might help, but
according to my man page, phys() is not implemented.

Any suggestions would be most appreciated (e-mail or post)!

Jeff Porter

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