Oct 31 2022 update
While my script below works fine as it is, Michael Sartain implemented a native executable that is much faster, along with additional functionality not present in my script (below). Worth checking out if you can spend a few seconds compiling it! I have also added contributed some PRs to align the functionality, so it should be pretty 1:1, just faster.
Upvote his answer on the Unix Stackexchange.
Original answer with script
I already answered this in the same thread on Unix Stackexchange as was mentioned by @cincodenada, but thought I could repost my ready-made answer here, seeing that no one really has something that works:
I have a premade script, inotify-consumers, that lists the top offenders for you:
INOTIFY INSTANCES
WATCHES PER
COUNT PROCESS PID USER COMMAND
------------------------------------------------------------
21270 1 11076 my-user /snap/intellij-idea-ultimate/357/bin/fsnotifier
201 6 1 root /sbin/init splash
115 5 1510 my-user /lib/systemd/systemd --user
85 1 3600 my-user /usr/libexec/xdg-desktop-portal-gtk
77 1 2580 my-user /usr/libexec/gsd-xsettings
35 1 2475 my-user /usr/libexec/gvfsd-trash --spawner :1.5 /org/gtk/gvfs/exec_spaw/0
32 1 570 root /lib/systemd/systemd-udevd
26 1 2665 my-user /snap/snap-store/558/usr/bin/snap-store --gapplication-service
18 2 1176 root /usr/libexec/polkitd --no-debug
14 1 1858 my-user /usr/bin/gnome-shell
13 1 3641 root /usr/libexec/fwupd/fwupd
...
21983 WATCHES TOTAL COUNT
INotify instances per user (e.g. limits specified by fs.inotify.max_user_instances):
INSTANCES USER
----------- ------------------
41 my-user
23 root
1 whoopsie
1 systemd-ti+
...
Here you quickly see why the default limit of 8K watchers is too little on a development machine, as just WebStorm instance quickly maxes this when encountering a node_modules folder with thousands of folders. Add a webpack watcher to guarantee problems …
Even though it was much faster than the other alternatives when I made it initially, Simon Matter added some speed enhancements for heavily loaded Big Iron Linux (hundreds of cores) that sped it up immensely, taking it down from ten minutes (!) to 15 seconds on his monster rig.
Later on, Brian Dowling contributed instance count per process, at the expense of relatively higher runtime. This is insignificant on normal machines with a runtime of about one second, but if you have Big Iron, you might want the earlier version with about 1/10 the amount of system time 🙂
How to use
inotify-consumers --help 😊 To get it on your machine, just copy the contents of the script and put it somewhere in your $PATH, like /usr/local/bin. Alternatively, if you trust this stranger on the net, you can avoid copying it and pipe it into bash over http:
$ curl -s https://raw.githubusercontent.com/fatso83/dotfiles/master/utils/scripts/inotify-consumers | bash
INOTIFY
WATCHER
COUNT PID USER COMMAND
--------------------------------------
3044 3933 myuser node /usr/local/bin/tsserver
2965 3941 myuser /usr/local/bin/node /home/myuser/.config/coc/extensions/node_modules/coc-tsserver/bin/tsserverForkStart /hom...
6990 WATCHES TOTAL COUNT
How does it work?
For reference, the main content of the script is simply this (inspired by this answer)
find /proc/*/fd \
-lname anon_inode:inotify \
-printf '%hinfo/%f\n' 2>/dev/null \
\
| xargs grep -c '^inotify' \
| sort -n -t: -k2 -r
Changing the limits
In case you are wondering how to increase the limits
$ inotify-consumers --limits
Current limits
-------------
fs.inotify.max_user_instances = 128
fs.inotify.max_user_watches = 524288
Changing settings permanently
-----------------------------
echo fs.inotify.max_user_watches=524288 | sudo tee -a /etc/sysctl.conf
sudo sysctl -p # re-read config