Metadata hit ratio

[Yannis Klonatos]

Hello all,

         Along with my other (yet pending :-( ) question/issue, I have 
another question (i hope this is the last :-) )
now.
         I would like to measure the hit ratio of the metadata accesses 
of XFS (inode+internal buffers). It is my
understanding that XFS uses its own data structures, and does not rely 
on the buffercache mechanisms of
the Linux kernel. However, even doing so, there may be cases that the 
metadata may not fit in the RAM,
and I/O operations are required to fetch them from the underlying 
storage. I have found out that there are
two places that XFS uses the submit_bio function. If i add some counters 
there, would it suffice to measure all
the metadata misses?
         Or is this information available in one (or more) of the 
xfs_stats counters? And if so, what do i need to sum
up in order to get the total metadata hit and miss ratio?

Thanks (again!) in advance,
Yannis Klonatos