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Old 02-09-2014, 05:04 AM   #1
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Registered: Feb 2014
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Smile Increasing POSIX message queue limit using - ulimit -q option

Hi All,

I Cannot find ulimit -q (to increase the limit on Message Queues) option on a specific Linux 2.6.32.XX kernel cross compiled for PPC 440, should i enable a kernel menu config build param ? I see this option available on my x86_64 RHEL 6.4 laptop.

I am looking for -- POSIX message queues (bytes, -q) but ulimit -a shows only the following options. NO -q

ulimit -a
-f: file size (blocks) unlimited
-t: cpu time (seconds) unlimited
-d: data seg size (kb) unlimited
-s: stack size (kb) 10240
-c: core file size (blocks) unlimited
-m: resident set size (kb) unlimited
-l: locked memory (kb) 64
-p: processes 1886
-n: file descriptors 1024
-v: address space (kb) unlimited
-w: locks unlimited

But i do see the option on my x86_64 RHEL 6.4 laptop kernel 2.6.32-358.11.1.el6.x86_64

ulimit -a
core file size (blocks, -c) unlimited
data seg size (kbytes, -d) unlimited
scheduling priority (-e) 0
file size (blocks, -f) unlimited
pending signals (-i) 29539
max locked memory (kbytes, -l) 64
max memory size (kbytes, -m) unlimited
open files (-n) 1024
pipe size (512 bytes, -p) 8
POSIX message queues (bytes, -q) 819200
real-time priority (-r) 0
stack size (kbytes, -s) 10240
cpu time (seconds, -t) unlimited
max user processes (-u) 1024
virtual memory (kbytes, -v) unlimited
file locks (-x) unlimited

I have already set the following limits in proc on PPC 440 Linux

echo 100 > /proc/sys/fs/mqueue/msg_max
echo 128 > /proc/sys/fs/mqueue/msgsize_max
echo 512 > /proc/sys/fs/mqueue/queues_max

but since the number of message needed by application is going above the limit - I get a ENOMEM error on mq_open after 100 mqs, i need over 120 mqs. I wanted to increase the ulimit -q limit to unlimited.

Note on this linux is cross compiled for PPC 440, not sure if this should make any difference

also i do not see the below 2 files in /etc.


I am guessing, some Linux Menu Config option is not enabled ?

Appreciate your inputs.

Cheers, newbee8


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