how does ulimit work

wastingtime · 02-02-2012, 01:58 AM

$ ulimit -m 150000 -v 500000
$ /usr/lib/thunderbird-9.0/thunderbird-bin

However

$ top
top - 23:46:50 up 4 days, 9:17, 6 users, load average: 0.33, 0.40, 0.43
Tasks: 129 total, 1 running, 128 sleeping, 0 stopped, 0 zombie
Cpu(s): 10.2%us, 2.8%sy, 0.0%ni, 87.0%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st
Mem: 1024220k total, 920192k used, 104028k free, 4176k buffers
Swap: 2096444k total, 0k used, 2096444k free, 385832k cached

PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
10545 user 1 0 475m 154m 31m S 0.0 15.4 0:30.89 firefox
9183 user 1 0 463m 168m 19m S 0.0 16.9 1:43.64 thunderbird-bin

How come thunderhog consumes more resident memory that ulimit allows?

jv2112 · 02-02-2012, 04:30 AM

man ulimit

Quote:

DESCRIPTION
The ulimit utility shall set or report the file-size writing limit
imposed on files written by the shell and its child processes (files of
any size may be read). Only a process with appropriate privileges can
increase the limit.

------------------------------------------------------

APPLICATION USAGE
Since ulimit affects the current shell execution environment, it is
always provided as a shell regular built-in. If it is called in a sepa‐
rate utility execution environment, such as one of the following:

nohup ulimit -f 10000
env ulimit 10000

it does not affect the file size limit of the caller's environment.

wastingtime · 02-02-2012, 05:46 AM

Yeah, I know about man ulimit.

How come thunderbird consumes more resident memory than what ulimit allows?

jv2112 · 02-03-2012, 04:34 AM

I just ran the same test on my system and thunderbird crashed because of lack of memmory. It appears to need it.

If you were doing all in the same shell I can only guess it is a permission issue.

Code:

[joe@Tux-Box ~]$ thunderbird 
Xlib:  extension "RANDR" missing on display ":0.0".
ReminderFox  clh(1)  {rmFx_cmdLine: [xpconnect wrapped nsICommandLine]}
out of memory
Segmentation fault

wastingtime · 02-03-2012, 09:35 AM

Yep, I speculate that ReimderFox extension, which I don't have installed, wants to gobble even more memory. This is so poorly designed it cannot handle out of memory error.

In your case ulimit seems to have done it's job though. My question is opposite: why thunderbird could allocate more memory that ulimit should have let it?