macos - How to limit memory of a OS X program? ulimit -v neither -m are working

Question

My programs run out of memory like half of the time I run them. Under Linux I can set a hard limit to the available memory using ulimit -v mem-in-kbytes. Actually, I use ulimit -S -v mem-in-kbytes, so I get a proper memory allocation problem in the program and I can abort.

But... ulimit is not working in OSX 10.6. I've tried with -s and -m options, and they are not working.

In 2008 there was some discussion about the same issue in MacRumors, but nobody proposed a good alternative. The should be a way a program can learn it's spending too much memory, or setting a limit through the OS.

Answer 1

After struggling with this myself (with limited success), I have determined there seems to be two ways to do it...

You can setup a launchd item for your executable.. The important part of the plist is a section, such as..

<key>SoftResourceLimits</key>
<dict>
    <key>Stack</key>
    <integer>10000000000</integer>
</dict>

There are various keys available... which can be found on Apple's MAN page.

Another way to do it, I think, is by setting a value in either /etc/launchd.conf (system) or /etc/launchd-usr.conf (peruser). For example, your launchd.conf could contain...

umask 002
limit stack 67104768 67104768
limit maxproc 3400 4500
limit maxfiles 256 unlimited
setenv PATH /opt/local/bin:/opt/local/sbin:/usr/bin:/bin:/usr/sbin:/sbin:/usr/local/bin:/usr/X11/bin

The documentation for all of launchd's functionality is shotty, if you ask me.. It's as if Apple might not care / want people outside their walls to actually understand how it all works. There is so much power to be had by mastering launchd and it's intricacies... but there are few concrete/official resources available as to how to properly implement them.