os::reserve_memory has been broken out into OS and CPU-specific variants most
probably for historical reasons (according to comments in the code it looks like
the only concrete reason it was done was to place the heap differently on
Solaris/x86). In recent fixes for 4852809 and 4925121 the variants in
os_linux_i486.cpp, os_linux_ia64.cpp, and os_linux_amd64.cpp were merged into
os_linux.cpp. For consistency's sake this should be done on the other platforms
as well. Presumably this code is not really CPU-specific although there are
subtle differences among the Solaris and Windows versions of this code.