Docker memory usage

Issue Type: Memory
OS Version: Linux MBOOT40.184 3.10.0-327.el7.x86_64 #1 SMP Thu Nov 19 22:10:57 UTC 2015 x86_64 x86_64 x86_64 GNU/Linux
App version:
Client:
Version: 18.09.1-rc1
API version: 1.39
Go version: go1.10.5
Git commit: bca0068
Built: Fri Dec 7 05:29:44 2018
OS/Arch: linux/amd64
Experimental: false

Server: Docker Engine - Community
Engine:
Version: 18.09.1-rc1
API version: 1.39 (minimum version 1.12)
Go version: go1.10.5
Git commit: bca0068
Built: Fri Dec 7 05:02:49 2018
OS/Arch: linux/amd64
Experimental: false

Steps to reproduce: Start docker

We see dockerd taking up upto 57MB RES Memory as shown below:

[root@MBOOT40 ~]# top -b -n1 | grep docker
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
7979 root 20 0 538992 57208 22780 S 0.0 3.0 0:00.20 dockerd

However, we were previously on an older docker distribution and the memory used was just 12 MB.

Client:
Version: 1.8.2-el7.centos
API version: 1.20
Package Version: docker-1.8.2-10.el7.centos.x86_64
Go version: go1.4.2
Git commit: a01dc02/1.8.2
Built:
OS/Arch: linux/amd64

Server:
Version: 1.8.2-el7.centos
API version: 1.20
Package Version:
Go version: go1.4.2
Git commit: a01dc02/1.8.2
Built:
OS/Arch: linux/amd64

[root@MBOOT40 ~]# top -b -n1

PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
1196 root 20 0 309092 12524 9384 S 0.0 0.7 0:00.38 docker

Why has memory usage gone up between these versions? Is there a stripped down version that can be built from source so that the memory footprint is low.

I am trying to use docker for an embeded platform where memory constraints require a low memory footprint.