Given the previous set of patches that integrate NFS with the VM +
pdflush memory control, and add mechanisms to cope with low memory
conditions, the time is now ripe to rip out the 256 outstanding
request limit, as well as the associated LRU list in the superblock,
and the nfs_flushd daemon.

The following patch offers a 30% speed increase on my test setup with
512MB of core memory (iozone using 4 threads each writing a 512MB file
over 100Mbit to a Solaris server). Setting mem=64m, I still see a 2-3%
speed increase.