mstat fails to run on cgroups v2

[peterzhu2118]

mstat fails to run on 22.04 and later due to switching to cgroups v2. It fails with the following error message:

2022/12/06 11:04:10 internal error: Read: EOF/0/[]byte{0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0}
2022/12/06 11:04:10 NewPoller: poll: cg.Stat: returned nil Memory stats

However, there is currently a workaround. However, the workaround will require modifying your bootloader to force it to boot with cgroups v1.

1. Open /etc/default/grub.
2. Replace the line GRUB_CMDLINE_LINUX="" with GRUB_CMDLINE_LINUX="systemd.unified_cgroup_hierarchy=0".
3. Run sudo update-grub to update your bootloader.
4. Reboot your system.