Can not increase default VM RAM size to over 2 GB

Hi all, on my MacBook Pro M1 and Parallels 16.5 I installed Ubuntu 20.04 on a new VM by specifying in VM settings to use 4 GB of RAM. The panel settings confirms that the RAM assigned to VM should be 4 GB but inside the VM from a shell if I run the command "free" I can see that only 2 GB are assigned to VM:

free
total used free shared buff/cache available
Mem: 1921796 1638772 96196 2976 186828 122736
Swap: 2097148 1607760 489388

I tried to change the RAM value assigned to VM also to 6 or 3 GB but nothing changed, the RAM visible from VM is always 2 GB. Do you know how to fix this issue?

 

Ok, found a fix by following this guide: https://kb.parallels.com/122687 By passing the boot flag "devices.pci_balloon=0" to VM, this ensures that Linux kernel is able to access all RAM specified into VM settings.