Bug: b/123559319, b/112824791, b/120287622 (partially)
Test: Android unit/integration tests, Linux unit tests,
GTS tests on Taimen, GTS tests on Crosshatch
Merge of http://go/wvgerrit/72483
This is a revert of http://go/ag/6216663. This addresses the
failures that led to the seg faults in the 64 bit Level 3 library. Cache
flushing must be done to the entire mmap'd page regardless of whether or
not we use the entire page. Since we now have to cache flush the entire
page, this gives us a performance hit due to us using the max page size.
To get around this, we reuse mmap'd pages only for the 95th percentile
page size or lower.
Change-Id: I14bc0d7e21faae6b6816ea589ba25f9661dcec93
9be36c1d4b