The show_mem() output does not include the total number of
pagecache pages.  This really limits the value of the debugging
information sent to the console and /var/log/messages file when OOM
kills occur. 
The attached patch includes the total pagecache pages in that output:

-------------------------------------------------
   Node 0 Normal: empty
   Node 0 HighMem: empty
> >>113032 pagecache pages
   Swap cache: add 0, delete 0, find 0/0, race 0+0
   Free swap  = 2031608kB
   Total swap = 2031608kB
   Free swap:       2031608kB
   523900 pages of RAM
   42142 reserved pages
   63864 pages shared
   0 pages swap cached
------------------------------------------------