[openib-general] Re: [PATCH 35 of 53] ipath - some interrelated stability and cleanliness fixes

[Dave Olson]

On Mon, 15 May 2006, Roland Dreier wrote:

| This looks like a pastiche of several patches.  Why can't it be split
| up into logical pieces?
| 
|  > Call dma_free_coherent without ipath_mutex held.
| 
| Why?  Doesn't freeing work with the mutex held?

Sure, that's the way the previous code worked.

We are seeing a bug (with both our driver native MPI processes and mthca mvapic),
where when 8 processes using "simultaneously exit", we get watchdogs and/or hangs
in the close routines.   Moving the freeing outside the mutex was an attempt
to see if we were running into some VM issues by doing lots of page unlocking
and freeing with the mutex held.   It seemed to help somewhat, but not to solve
the problem.

It also allows other processes to open and close in a somewhat more timely
fashion.

Dave Olson
olson at unixfolk.com
http://www.unixfolk.com/dave