Restore optimizations to reduce TLB shootdowns. Alan Cox pointed out that they are really useful for sendfile().
Restore optimizations to reduce TLB shootdowns.
Alan Cox pointed out that they are really useful for
sendfile().

MFC after:	3 days

jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase