Hi try this: cat /proc/buddyinfo
It will display how manyblocks are available at which NUMA node.
Look on the internet on how to interpretate the data.
The right most numbers are the 4MB DMA blocks.
After a fresh reboot the most 4MB blocks are available, don't
know if a function exists to gather smaller blocks into a large one
look at these links:
http://lwn.net/Articles/211505/
http://puschitz.com/pblog/?p=28