Firefox

• about:config
• browser.tabs.allowTabDetach

References:

• Limit Memory Usage using cgroups
• https://gist.github.com/hardfire/7e5d9e7ce218dcf2f510329c16517331
• https://gist.github.com/avoidik/1c7c53f02461f716aabebf3372a6199d

But now we have some modern systemd based tools.

https://wiki.archlinux.org/title/cgroups

/usr/local/bin/firefox

#!/bin/bash
systemd-run --user -G --scope --unit=run-firefox -p OOMPolicy=continue -p MemoryMaxigh=4G -p MemoryMax=5G -p MemorySwapMax=2G -p "CPUQuota=200%" /usr/bin/firefox "$@"

or

/usr/local/bin/firefox

#!/bin/bash
systemd-run --user -G --scope --unit=run-firefox -p OOMPolicy=continue -p MemoryHigh=50% -p MemoryMax=60% -p MemorySwapMax=2G -p "CPUQuota=200%" /usr/bin/firefox "$@"

See MemoryMax

Verify limits:

systemctl list-units --user --type scope
systemctl status --user run-firefox.scope
 
 Memory: 201.3M (max: 2.0G swap max: 2.0G available: 1.8G)

Modify limits without restarting firefox:

systemctl set-property --user run-firefox.scope MemoryMax=8G MemorySwapMax=10G

sudo apt install firejail
 
firejail --noprofile --rlimit-as=5g firefox

       --rlimit-as=number
              Set the maximum size of the process's virtual memory (address space) in bytes.  Use k(ilobyte), m(egabyte) or g(igabyte) for size suffix (base 1024).

Using_Firejail_by_default