question about tmpfs

[basti]

Hello,

I have a question about tmpfs.

On my raspberry pi I with only 256 MB RAM df looks like.

root at pi:~# df -h
Filesystem      Size  Used Avail Use% Mounted on
/dev/root        15G  2.0G   13G  14% /
devtmpfs        111M     0  111M   0% /dev
tmpfs           115M     0  115M   0% /dev/shm
tmpfs           115M   13M  102M  11% /run
tmpfs           5.0M  4.0K  5.0M   1% /run/lock
tmpfs           115M     0  115M   0% /sys/fs/cgroup
/dev/mmcblk0p1   56M   20M   37M  36% /boot
tmpfs            23M     0   23M   0% /run/user/33
tmpfs            23M     0   23M   0% /run/user/0

Is tmpfs "overload"?
What happens when a add a new tmpfs partition e.g for squid?

Is there a way to manipulate the size of the "default" tmpfs shown
above? In /etc/fstab I cant found anything about tmpfs.

root at pi:~# cat /etc/fstab
proc            /proc           proc    defaults          0       0
/dev/mmcblk0p1  /boot           vfat    defaults          0       2
/dev/mmcblk0p2  /               ext4    defaults,noatime  0       1
# a swapfile is not a swap partition, no line here
#   use  dphys-swapfile swap[on|off]  for that
root at pi:~#