wacky hangs on 2.5.69-mm7, -mm3

[Cliff White]

Andrew, 
we are running a few tests on 2.5.69, -mm7, and -mm3 and having
some wacky hangs.

Booted both kernels with default IO scheduler. 

The Reaim test running against -mm7 (AIM rewrite) hangs, with a large number 
of 'sync' commands that never complete and are unkillable. (Various tests call 
'sync') System is a 4-CPU PIII , two of the CPU's are stuck at 100% iowait. 
Filesystem is ext2.  Same kernel run with elevator=deadline ran okay. -mm6 ran 
okay, but
was not especially performant. (separate mail)

The -mm3 kernel is running DBT2 on a 8-CPU machine, with raw devices. Ten 
minutes
into the run, all IO ceases, iostat shows devices 133% busy, workload stops.
'ps -aef' never completes. Previous run with elevator=noop was fine. 

We've left the 8-way as is if you want a look.
cliffw
maryedie
OSDL