mjhjmtu

I use inotifywait for event trigger which put file.

When many files are watched by inotifywait, when max_user_watches is exceeded, the following error occurs.

Terminating since out of inotify watches.#012Consider increasing /proc/sys/fs/inotify/max_user_watches

It is necessary to tune /proc/sys/fs/inotify/max_user_watches, but is it possible to check the current file watch number?

Is there a way to check like file-nr in file descriptor?

I wish I was able to answer with something smarter, but the only way I found to count the inotify(7) watches set by a user is this:

find /proc/*/fd -user "$USER" -lname anon_inode:inotify 
 -printf '%hinfo/%fn' 2>/dev/null |
 xargs cat | grep -c '^inotify'

Change "$USER" with the actual user you want info about; "`id -u`" for the current user. Notice that the max_user_watches is a per-user limit, not per process, or per inotify instance / file descriptor.

This will first find all open file descriptors created by inotify_init*(2), and will then look into the corresponding /proc/PID/fdinfo/FD file for the info about the watch descriptors added with inotify_add_watch(2) to each of them (look into the proc(5) manpage under /proc/[pid]/fdinfo/ for a description of the inotify-specific entries). The -c option of grep will let it print a count of all lines that match a pattern.

Note: the counter for inotify_watches is kept just like other per-user counters in a struct ucounts referenced from the user namespace structure -- see include/linux/user_namespace.h; but I wasn't able to find any interface exposing those counters to userland.

I cobbled together this little script based on @mosvy's answer.

$ inotify-consumers 

 INOTIFY
 WATCHER
 COUNT PID CMD
----------------------------------------
 7111 3079 node /home/carlerik/dev/nimble-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
 14 1191 /lib/systemd/systemd --user
 10 1371 /usr/bin/gnome-shell
 9 2459 update-notifier
 7 1635 nautilus-desktop
 5 1191 /lib/systemd/systemd --user
 2 1536 /usr/lib/gnome-settings-daemon/gsd-sound
 2 1452 /usr/lib/evolution/evolution-source-registry
 2 1429 ibus-daemon --xim --panel disable
 2 1248 /usr/bin/dbus-daemon --session --address=systemd: --nofork --nopidfile --systemd-activation --syslog-only
 1 1863 /usr/lib/gnome-terminal/gnome-terminal-server
 1 1713 /usr/lib/evolution/evolution-addressbook-factory
 1 1678 /usr/lib/ibus/ibus-engine-simple
 1 1625 /usr/lib/evolution/evolution-calendar-factory
 1 1560 /usr/lib/gnome-settings-daemon/gsd-housekeeping
 1 1556 /usr/lib/gnome-settings-daemon/gsd-color
 1 1499 /usr/lib/gvfs/gvfs-afc-volume-monitor
 1 1487 /usr/lib/gnome-online-accounts/goa-identity-service
 1 1480 /usr/lib/gvfs/gvfs-udisks2-volume-monitor
 1 1460 /usr/lib/gnome-online-accounts/goa-daemon
 1 1440 /usr/lib/ibus/ibus-portal
 1 1435 /usr/lib/ibus/ibus-x11 --kill-daemon
 1 1433 /usr/lib/ibus/ibus-dconf
 1 1410 /usr/bin/pulseaudio --start --log-target=syslog
 1 1410 /usr/bin/pulseaudio --start --log-target=syslog
 1 1410 /usr/bin/pulseaudio --start --log-target=syslog
 1 1371 /usr/bin/gnome-shell
 1 1352 /usr/bin/dbus-daemon --config-file=/usr/share/defaults/at-spi2/accessibility.conf --nofork --print-address 3
 1 1254 /usr/lib/gnome-session/gnome-session-binary --session=ubuntu
 1 1254 /usr/lib/gnome-session/gnome-session-binary --session=ubuntu
 1 12287 /home/carlerik/.sdkman/candidates/java/current/bin/java -classpath /usr/share/maven/boot/plexus-classworlds-2.x.jar -Dcl
 1 1191 /lib/systemd/systemd --user