1. This version of the GM nal requires an unreleased extension to the GM API to
   map physical memory: gm_register_memory_ex_phys(). This allows it to avoid
   ENOMEM problems associated with large contiguous buffer allocation.

2. ./configure --with-gm=<path-to-gm-source-tree> \
   [--with-gm-install=<path-to-gm-installation>]

   If the sources do not support gm_register_memory_ex_phys(), configure flags
   an error. In this case you should apply the patch and rebuild and re-install
   GM as directed in the error message.

   By default GM is installed in /opt/gm. If an alternate path was specified to
   <GM-sources>/binary/GM_INSTALL, you should also specify --with-gm-install
   with the same path.

3. The GM timeout is 300 seconds; i.e. the network may not release resources
   claimed by communications stalled with a crashing node for this time.
   Default gmnal buffer tuning parameters (see (4) below) have been chosen to
   minimize this problem and prevent lustre having to block for resources.
   However in some situations, where all network buffers are busy, the default
   lustre timeout (various, scaled from the base timeout of 100 seconds) may be
   too small and the only solution may be to increase the lustre timeout
   dramatically.

4. The gmnal has the following module parameters...

   gmnal_port              The GM port that the NAL will use (default 4) 
                           Change this if it conflicts with site usage.

   gmnal_ntx               The number of "normal" transmit descriptors (default
                           32). When this pool is exhausted, threads sending
                           and receiving on the network block until in-progress
                           transmits have completed. Each descriptor consumes 1
                           GM_MTU sized buffer. 

   gmnal_ntx_nblk          The number of "reserved" transmit descriptors
                           (default 256). This pool is reserved for responses to
                           incoming communications that may not block. Increase
                           only if console error messages indicates the pool
                           has been exhausted (LustreError: Can't get tx for
                           msg type...) Each descriptor consumes 1 GM_MTU sized
                           buffer.

   gmnal_nlarge_tx_bufs    The number of 1MByte transmit buffers to reserve at
                           startup (default 32). This controls the number of
                           concurrent sends larger that GM_MTU. It can be
                           reduced to conserve memory, or increased to increase
                           large message sending concurrency. 

   gmnal_nrx_small         The number of GM_MTU sized receive buffers posted to
                           receive from the network (default 128). Increase if
                           congestion is suspected, however note that the total
                           number of receives that can be posted at any time is
                           limited by the number of GM receive tokens
                           available. If there are too few, this, and
                           gmnal_nrx_large are scaled back accordingly. 

   gmnal_nrx_large         The number of 1MByte receive buffers posted to
                           receive from the network (default 64). Increase if
                           the number of OST threads is increased. But note
                           that the total number of receives that can be posted
                           at any time is limited by the number of GM receive
                           tokens available. If there are too few, this, and
                           gmnal_nrx_small are scaled back accordingly. 

5. Network configuration for GM is done in an lmc script as follows...

   GM2NID=${path-to-lustre-tree}/portals/utils/gmnalnid

   ${LMC} --node some_server --add net --nettype gm --nid `$GM2NID -n some_server`

   ${LMC} --node client --add net --nettype gm --nid '*'