spurious out of swap kills

[bob prohaska]

Not sure this is relevant, but in compiling chromium on a Pi3 with 6 GB
of swap the job completed successfully some months ago, with peak swap 
use around 3.5 GB. The swap layout was sub-optimal, with a 2 GB partition
combined with a 4 GB partition. A little over 4GB total seems usable. 

A few days ago the same attempt stopped with a series of OOMA kills,
but in each case simply restarting allowed the compile to pick up
where it left off and continue, eventually finishing with a runnable
version of chromium. In this case swap use peaked a little over 4 GB.

Might this suggest the machine isn't freeing swap in a timely manner?

Thanks for reading,

bob prohaska