155
votes
Limit memory usage for a single Linux process
On any systemd-based distro you can also use cgroups indirectly through systemd-run. E.g. for your case of limiting pdftoppm to 500M of RAM, starting with cgroupsv2, you can simply do:
systemd-run --...
- 5,600
89
votes
Accepted
Why can't I crash my system with a fork bomb?
You probably have a Linux distro that uses systemd.
Systemd creates a cgroup for each user, and all processes of a user belong to the same cgroup.
Cgroups is a Linux mechanism to set limits on ...
- 1,687
59
votes
Modify ulimit (open files) of a specific process
To change the limits of a running process, you may use the utility command prlimit.
prlimit --pid 12345 --nofile=1024:1024
What that does internally is to call setrlimit(2). The man page of prlimit ...
- 2,198
31
votes
How to check ulimit usage
Output the current user's percentage of open files, proc, and pending signals, by several inconvenient methods and standard tools:
paste <(grep 'open files\|processes\|pending signals' \
...
- 7,393
28
votes
How calculate the number of files which can be passed as arguments to some command for batch processing?
Let xargs do the calculation for you.
printf '%s\0' files/* | xargs -0 mv -t new_files_dir
26
votes
Accepted
sudo: setrlimit(RLIMIT_CORE): Operation not permitted
a fix has been applied to sudo 1.8.31p1 and is already in 1.9 however this warning has a work around ... just issue
echo "Set disable_coredump false" >> /etc/sudo.conf
for details see https://...
- 2,995
17
votes
/etc/security/limits.conf not applied
It is recommended to create /etc/systemd/*.d/ directories instead of editing /etc/systemd/system.conf and /etc/systemd/user.conf directly.
Create a new file /etc/systemd/system.conf.d/limits.conf ...
- 1,202
16
votes
Why can't I crash my system with a fork bomb?
This won't crash modern Linux systems anymore anyway.
It creates hoards of processes but doesn't really burn all that much CPU as the processes go idle. You run out of slots in the process table ...
- 1,965
15
votes
Meaning of the values for ulimit memlock flag
Yes you are right. Check the definition of memlock here
memlock
maximum locked-in-memory address space (KB)
This is memory that will not be paged out. It is frequently used by
database management ...
- 251
14
votes
How to Throttle per process I/O to a max limit?
The answer of fche is a very good hint, thanks for that, although it dosn't really solve the problem cause the question was to limit a process to a specific bandwidth.
I would suggest something like ...
- 267
13
votes
ulimit vs file-max
ulimit shows the per-process maximum. The two files under /proc shows system-wide numbers.
From ServerFault:
file-max is the maximum File Descriptors (FD) enforced on a kernel level, which cannot be ...
- 356k
12
votes
Systemd LimitNOFILE capped to 4096
Late answer;
limits.conf is not used when systemd is running (limits.conf is for non-systemd systems).
The file you actually want is; /etc/systemd/system.conf - this is the global config. Then you ...
- 121
10
votes
Accepted
How to cause "Argument list too long" error?
Using getconf ARG_MAX to generate a long list of x and calling an external utility with that as its argument would generate an "Argument list too long" error:
$ /bin/echo $( perl -e 'print "x" x $...
- 356k
10
votes
Accepted
Change the resource limits (ulimit / rlimit) of a running process
I've figured it out.
On some kernels (e.g. 2.6.32+), at least on CentOS/RHEL, you can change the resource limits of a running process using /proc/<pid>/limits, e.g.:
$ grep "open files" /proc/...
- 2,314
10
votes
Accepted
ulimit for stack size - per process or per thread limit?
SUMMARY
For the main thread, you have to call setrlimit() (perhaps by using ulimit) before the process is started in order to ensure the larger stack size is effective.
For threads started by the ...
- 4,008
10
votes
Accepted
Can't set ulimit -n like I want to
# ulimit -n 1048576
# ulimit -n 2000000
bash: ulimit: open files: cannot modify limit: Operation not permitted
# sysctl fs.nr_open
fs.nr_open = 1048576
# sysctl fs.nr_open=2000000
fs.nr_open = 2000000
...
- 148k
9
votes
Why does the following way not change core file limit size?
According to the manpage, ulimit "provides control over the resources available to the shell and to processes started by it". So the ulimit value is valid for the current shell.
You are invoking ...
- 32.4k
9
votes
Why can't I crash my system with a fork bomb?
Back in the 90's I accidentally unleashed one of these on myself. I had inadvertently set the execute bit on a C source file that had a fork() command in it. When I double-clicked it, csh tried to run ...
- 291
9
votes
Accepted
Chromium browser: exceed data ulimit
Why does chromium have different limits than all other programs?
Chromium may look like a simple application but it is not, first there is the multi-threading which makes chromium run multiple process ...
- 15.1k
8
votes
Accepted
Is setting ulimit -v sufficient to avoid memory leak
Some description about how ulimit works:
ulimit has deal with setrlimit and getrlimit system calls. It's easy to ensure by strace-ing of bash process (ulimit is component of the bash). I set 1024kb ...
- 4,410
8
votes
How to cause "Argument list too long" error?
On many Linux distributions, you can find out what's the current value of ARG_MAX by running
getconf ARG_MAX
A simple way to generate the message "Argument list too long" is to actually supply a long ...
- 10.8k
7
votes
Limit memory usage for a single Linux process
While this isn't what the OP originally asked for, but for the sake of completeness, for processes that are already running, I use prlimit
E.G. $ prlimit -v1073741824 -pid <xx>
Sets the max ...
- 345
7
votes
Limit memory usage for a single Linux process
cgroupsv2 update (Ubuntu 22.04 - 24.10)
Things have moved around a bit. Compared to https://unix.stackexchange.com/a/125024/32558 now you now need:
sudo apt install cgroup-tools
sudo cgcreate -a $USER:...
7
votes
How to increase the maximum number of open files on Fedora?
The problem here is that the GUI (and gnome-terminal) are started by systemd --user, which does not read from /etc/security/limits.conf. Instead, you should edit /etc/systemd/user.conf and /etc/...
- 171
7
votes
Accepted
Figure out which process forks too many threads
ps -eo nlwp,pid,args --sort nlwp
Would show a list of processes sorted by their number of threads.
For a top-like view of that, you can always do:
watch -n 1 'ps -eo nlwp,pid,args --sort -nlwp | ...
- 586k
7
votes
Enabling core files on CentOS 8.1
Your core dumps are probably in /var/lib/systemd/coredump (unless you've changed your systemd configuration to put them somewhere else). Use coredumpctl list to see what core dumps are available, and ...
- 1,306
7
votes
Accepted
Is the kilobyte used by time and ulimit commands either 1000 (SI) or 1024 (old school) bytes?
It is kibibytes (1024), those are raw interfaces to the getrusage()/ setrlimit() APIs. Those documentations are inaccurate (or old-school as you say).
Also note that the resource limits/accountings ...
- 586k
6
votes
How to cause "Argument list too long" error?
Instead of listing all the files on the system, which takes forever and doesn't work on sparse systems, the command
/bin/echo {1..200000}
is a much faster (163ms) way to generate the error. For me ...
- 3,538
Only top scored, non community-wiki answers of a minimum length are eligible