significantly increased memory usage after upgrade to Gluon v2020.1.x

[rotanid]

After updating from v2019.1.2 to v2020.1.2 memory usage increased.
The increase in our network is from average ~60% to ~70% on an idle node and at least 5% more on an active node. (with 32M memory)
On devices with only 32M memory, this leads to frequent reboots.
On devices with more memory, the increase can mostly also be seen but is not problematic.

Our firmware for these devices did not change in other ways with this Gluon version bump which could affect the memory usage.

please find attached the memory graphs of 4 32M devices and 2 64M devices before and after the firmware upgrade.

as far as i know, others also observed the issues as reported on the Gluon IRC channel for weeks.

[rotanid]

i can confirm that #2036 fixes the reported issue, 9 of our 10 test devices have an uptime of around 2 days by now.