[tremon]

  $ grep tmpfs /proc/mounts
  udev /dev devtmpfs [..]
  tmpfs /run tmpfs [..]
  tmpfs /run/lock tmpfs [..]
  tmpfs /run/shm tmpfs [..]
  tmpfs /tmp tmpfs [..]
  cgroup_root /sys/fs/cgroup tmpfs  [..]

If each of those can take up 50% of ram, this is still a big problem. I don't know what defaults Debian uses nowadays, because I have TMPFS_SIZE=1% in /etc/default/tmpfs so my system is explicitly non-default.

[NekkoDroid]

Sure, but counterpoint: if a process is already writing that much in multiple of those directories, who knows what its writing in other directories that aren't backed by RAM.