bufferpool@2.0 tune eviction params

bufferpool tries to manage memory consumption as low as 15MB usually.
Since it is too harsh for graphic input buffer use cases, if # of
buffers are under certain threshold make bufferpool ignore total memory
consumption.

Bug: 141605804
Change-Id: I20bd0438fede018e26984e0e3bc9a2007b0bc29b
1 file changed