LGTM!

LGTM

unlimited is still a number, just that it's a really high number.

@cpuguy83 is there a way to set no limit? If setting unlimited does still apply a limit, I wonder if #24307 (and this PR) has any benefits.

@cyphar did you benchmark the difference before/after applying #24307?

@thaJeztah According to the reporter of the bug, their benchmark time almost halved (from ~130 minutes to ~80) after setting the ulimits to be unlimited. I saw similar speedups while testing. Note that this only really affects cases where you open and close an unspeakably large number of files for short periods of time. It's possible that it's a systemd-specific issue (I wouldn't be surprised) but it makes sense to me that having a resource limit for the number of open files would cause quite a lot of overhead.

@cpuguy83 It looks like for RLIMIT_NOFILE Linux doesn't use RLIM_INFINITY as a special value specifically for the fastpath. So I'm not really sure why there is a performance impact -- it might be some weird quirk of rpm that causes this to happen.

In fact you don't appear to be able to set RLIMIT_NOFILE to unlimited anyway:

ulimit -n unlimited
bash: ulimit: open files: cannot modify limit: Operation not permitted

It is bounded by /proc/sys/fs/file-max. So that line is not doing anything at all. So it can only be the process limit that is having an effect, if anything there will probably be a lower file limit than before as it was not being raised.

@justincormack hm, that's weird I think it tried that, but maybe I messed up and only tried on ulimit -u 😊 I see the man page mentions;

-n The maximum number of open file descriptors (most systems do not allow this value to be set)

Looks like you can only set a numeric value, that's lower or equal to 1048576, but not a higher one;

ulimit -n 1048576

ulimit -n 1048577
bash: ulimit: open files: cannot modify limit: Operation not permitted

but that limit doesn't match /proc/sys/fs/file-max;

cat /proc/sys/fs/file-max
398153

I'm trying that in a container, so possibly that's related there

So, does setting LimitNOFILE=infinity in systemd work? And why? Or is it silently ignored?

Try it outside a container, docker may already have that limit set...
On 13 Jul 2016 12:51 p.m., "Sebastiaan van Stijn" [email protected]
wrote:

@justincormack https://github.com/justincormack hm, that's weird I
think it tried that, but maybe I messed up and only tried on ulimit -u 😊
I see the man page mentions
http://man7.org/linux/man-pages/man1/bash.1.html;

-n The maximum number of open file descriptors (most systems do not allow
this value to be set)

Looks like you can only set a numeric value, that's lower or equal to
1048576, but not a higher one;

ulimit -n 1048576

ulimit -n 1048577
bash: ulimit: open files: cannot modify limit: Operation not permitted

but that limit doesn't match /proc/sys/fs/file-max;

cat /proc/sys/fs/file-max
398153

I'm trying that in a container, so possibly that's related there

—
You are receiving this because you were mentioned.
Reply to this email directly, view it on GitHub
#24555 (comment), or mute
the thread
https://github.com/notifications/unsubscribe/AAdcPMGGjZNiOldl4tMntHJAMjmyyWjyks5qVNE-gaJpZM4JK1Uw
.

nope, looks to be the same;

root@dockr:~# ulimit -n 1048576
root@dockr:~# ulimit -n 1048577
-bash: ulimit: open files: cannot modify limit: Operation not permitted
root@dockr:~# ulimit -n unlimited
-bash: ulimit: open files: cannot modify limit: Operation not permitted

cat /proc/sys/fs/file-max
100809

ok that limit is hardcoded http://stackoverflow.com/questions/1212925/on-linux-set-maximum-open-files-to-unlimited-possible

Updated to only set nproc, and updated the systemd unit file accordingly; @cyphar can you confirm if setting LimitNOFILE=infinity actually worked? The systemd documentation seems to indicate it accepts the same values as ulimit -n; https://www.freedesktop.org/software/systemd/man/systemd.exec.html#id-1.7.2.29.17.3

LGTM

LGTM

@thaJeztah LimitNOFILE=infinity definitely works. I'm currently running a Docker daemon with that limit set.