How do I find out what inotify watches have been registered?

Question

I have my inotify watch limit set to 1024 (I think the default is 128?). Despite that, yeoman, Guard and Dropbox constantly fail, and tell me to up my inotify limit. Before doing so, I'd like to know what's consuming all my watches (I have very few files in my Dropbox).

Is there some area of /proc or /sys, or some tool I can run, to find out what watches are currently registered?

Answer 1

inotify filesystem options

sysctl fs.inotify

opened files

lsof | grep inotify | wc -l

Increase the values like this

• sysctl -n -w fs.inotify.max_user_watches=16384
• sysctl -n -w fs.inotify.max_user_instances=512

Answer 2

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:

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I have a premade script, inotify-consumers, that lists the top offenders for you (a newer version also lists the username owning the process, see below):

$ time inotify-consumers       INOTIFY    WATCHER     COUNT     PID     CMD ----------------------------------------     6688    27262  /home/dvlpr/apps/WebStorm-2018.3.4/WebStorm-183.5429.34/bin/fsnotifier64      411    27581  node /home/dvlpr/dev/kiwi-frontend/node_modules/.bin/webpack --config config/webpack.dev.js       79     1541  /usr/lib/gnome-settings-daemon/gsd-xsettings       30     1664  /usr/lib/gvfs/gvfsd-trash --spawner :1.22 /org/gtk/gvfs/exec_spaw/0       14     1630  /usr/bin/gnome-software --gapplication-service     ....      7489  WATCHERS TOTAL COUNT  real    0m0.099s user    0m0.042s sys 0m0.062s 

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.

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          979   3954 myuser /usr/local/bin/node /home/myuser/.config/coc/extensions/node_modules/coc-tsserver/node_modules/typescript/li            1   7473 myuser /usr/local/bin/node --no-warnings /home/myuser/dev/dotfiles/common-setup/vim/dotvim/plugged/coc.nvim/build/i            1   3899 myuser /usr/local/bin/node --no-warnings /home/myuser/dev/dotfiles/common-setup/vim/dotvim/plugged/coc.nvim/build/i          6990  WATCHERS 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