Snap memory quota are ignored by some snap packages


I tried to limit the memory usage of both firefox and chromium snap using the following commands:

snap set-quota memlimit-chromium --memory=4GB chromium

snap set-quota memlimit-firefox --memory=4GB firefox

However, even after restarting chrome of firefox, quotas don’t seem to be enforced:

~ $ snap quotas
Quota              Parent  Constraints    Current
memlimit-chromium          memory=4.00GB  
memlimit-firefox           memory=4.00GB  

~ $ snap quota memlimit-firefox
name:  memlimit-firefox
  memory:  4.00GB
  memory:  0B
  - firefox

~ $ ps -ef | grep -c -E "firefox"

~ $ ps -ef | grep -c -E "chrome"

i use snap on ubuntu 23.04.

~ $ snap version
snap    2.59.5
snapd   2.59.5
series  16
ubuntu  23.04
kernel  6.2.0-25-generic

~ $ snap list | grep -E "firefox|chromium"
chromium                        114.0.5735.198              2529   latest/stable  canonical**     -
firefox                         115.0b9-1                   2825   latest/beta    mozilla**       -

i followed this documentation:

and did not find any related issue on:

I did set experimental.quota-groups to true before upgrading to ubuntu 23.04 and did not modify this setting (but from snapd release notes this should not be necessary anymore)

~ $ sudo snap get system experimental.quota-groups

Did i miss something ? Cheers,