Cache seems to be paged out

[allnode]

To improve the performance of Search, I use the Plomino Cache function to save in the memory cache the search results:
See: http://dmcbeam.org/olmsted-county-community-health/frmWideSearchGeneralFront

And generally it works well. However, I am finding the cached result is transient. I am not sure what caused it to be "decached". I suspect that it may have something to do with my Plone server memory needs to be paged out when certain conditions happen. Is there some action I can take to expand the reserved memory size so that my cached search results don't get paged out?

https://github.com/plomino/Plomino/wiki/HOW-TO-Use-cache-to-improve-performances