Bug#1082920: gnome-shell on Wayland has different soft limit for open file descriptors than in X11

[Binay Devkota]

Package: gnome-shell
Version: 46.4-1
Severity: important

Using debian unstable with linux version 6.10.11 and both sessions have
same default settings. I do not have any custom settings set, I have
checked these files:

/etc/security/limits.conf
/etc/security/limits.d/*.conf 
/etc/sysctl.conf
/etc/sysctl.d/*.conf
/etc/systemd/system.conf
/etc/systemd/user.conf

There are no systemd overrides for following services. 

Here is how it looks like:

user at home:~$ echo $XDG_SESSION_TYPE
wayland
user at home:~$ systemctl show gnome-shell.service  | grep NOFILE
LimitNOFILE=1073741816
LimitNOFILESoft=1073741816
user at home:~$ systemctl show gnome-shell-wayland.service  | grep NOFILE
LimitNOFILE=1073741816
LimitNOFILESoft=1073741816
user at home:~$ systemctl show user at 1000.service  | grep NOFILE
LimitNOFILE=524288
LimitNOFILESoft=1024
user at home:~$ systemctl show gnome-shell-wayland.service  | grep NOFILE
LimitNOFILE=1073741816
LimitNOFILESoft=1073741816
user at home:~$ systemctl show gdm.service  | grep NOFILE
LimitNOFILE=524288
LimitNOFILESoft=1024
user at home:~$ cat /proc/$(pgrep gnome-shell$)/limits
Limit                     Soft Limit           Hard Limit          
Units     
Max cpu time              unlimited            unlimited           
seconds   
Max file size             unlimited            unlimited           
bytes     
Max data size             unlimited            unlimited           
bytes     
Max stack size            8388608              unlimited           
bytes     
Max core file size        0                    unlimited           
bytes     
Max resident set          unlimited            unlimited           
bytes     
Max processes             127437               127437              
processes 
Max open files            1073741816           1073741816          
files     
Max locked memory         4196806656           4196806656          
bytes     
Max address space         unlimited            unlimited           
bytes     
Max file locks            unlimited            unlimited           
locks     
Max pending signals       127437               127437              
signals   
Max msgqueue size         819200               819200              
bytes     
Max nice priority         0                    0                    
Max realtime priority     0                    0                    
Max realtime timeout      200000               200000               us
====

Then on X11

user at home:~$ echo $XDG_SESSION_TYPE
x11
user at home:~$ systemctl show gnome-shell.service  | grep NOFILE
LimitNOFILE=1073741816
LimitNOFILESoft=1073741816
user at home:~$ systemctl show gnome-shell-wayland.service  | grep NOFILE
LimitNOFILE=1073741816
LimitNOFILESoft=1073741816
user at home:~$ systemctl show user at 1000.service  | grep NOFILE
LimitNOFILE=524288
LimitNOFILESoft=1024
user at home:~$ systemctl show gnome-shell-wayland.service  | grep NOFILE
LimitNOFILE=1073741816
LimitNOFILESoft=1073741816
user at home:~$ systemctl show gdm.service  | grep NOFILE
LimitNOFILE=524288
LimitNOFILESoft=1024
user at home:~$ cat /proc/$(pgrep gnome-shell$)/limits
Limit                     Soft Limit           Hard Limit          
Units     
Max cpu time              unlimited            unlimited           
seconds   
Max file size             unlimited            unlimited           
bytes     
Max data size             unlimited            unlimited           
bytes     
Max stack size            8388608              unlimited           
bytes     
Max core file size        0                    unlimited           
bytes     
Max resident set          unlimited            unlimited           
bytes     
Max processes             127437               127437              
processes 
Max open files            1024                 1073741816          
files     
Max locked memory         4196806656           4196806656          
bytes     
Max address space         unlimited            unlimited           
bytes     
Max file locks            unlimited            unlimited           
locks     
Max pending signals       127437               127437              
signals   
Max msgqueue size         819200               819200              
bytes     
Max nice priority         0                    0                    
Max realtime priority     0                    0                    
Max realtime timeout      200000               200000               us
===

As you can see "Max open files" is 1024 on X11 and 1073741816 in
Wayland. 

Because of this I am running into an issue while launching flatpak apps
through ArcMenu extension or actually any xdg-open request which is
handled by flatpak application through a gnome extension. As brwap
tries to close all the open file descriptors before launching the app,
the 1073741816 limit causes very slow start of the app.