MFC r281738:
Change wcommitsize default from one empirical value to another.
The new value is more predictable with growing RAM size:
hibufspace maxvnodes old new
i386:
256MB 32980992 15800 2198732 2097152 2GB 94027776 107677 878764 4194304
amd64:
256MB 32980992 15800 2198732 2097152 1GB 114114560 68062 1678155 4194304 4GB 217055232 111807 1955452 4194304 16GB 1717846016 337308 5097465 16777216 64GB 1734918144 1164427 1490479 16777216 256GB 1734918144 4426453 391983 16777216