What arguments to blogbench are you using and how long does it run before it hits the malloc panic?
I found one possible path where inodes can build up but it still
doesn't feel quite right because even that path has upwards of a
2-second tsleep. With so many blogbench threads running in
parallel it could be the cause but it still ought to take a while
to build up that many extra inodes. I think I need to reproduce the
problem locally to determine if that path is the cause.
-Matt
