From David Hansen, Bill Irwin, Martin Bligh.

"It's easier to cat /proc/buddyinfo than to beg users to press
 shift-scrolllock on a machine millions of miles away.  Order 1 and 2
 memory allocations are common.  Memory fragmentation is a problem
 under some workloads, and this is a useful tool for helping diagnose
 these problems."

The following patch exports some information about the buddy allocator.

Each column of numbers represents the number of pages of that order
which are available.  In this case, there are 5 chunks of
2^2*PAGE_SIZE available in ZONE_DMA, and 101 chunks of 2^4*PAGE_SIZE
availble in ZONE_NORMAL, etc...  This information can give you a good
idea about how fragmented memory is and give you a clue as to how big
an area you can safely allocate.

Node 0, zone      DMA      0      4      5      4      4      3 ...
Node 0, zone   Normal      1      0      0      1    101      8 ...
Node 0, zone  HighMem      2      0      0      1      1      0 ...