PLEASE TEST: IPI deadlock avoidance patch

[Garance A Drosihn]

At 12:05 PM -0700 8/22/04, Doug White wrote:
>Hey folks,  [...]   please try this patch:
>
>http://people.freebsd.org/~dwhite/smp_rv_mtx.patch
>
>This patch avoids a deadlock between the smp_rendezvous()
>mechanism and TLB shootdowns via pmap by forcing them to
>share a mutex.

I have completed a series of buildworlds with -j3 to -j10 with
no problem.  I then started up a "folding at home" client, and
repeated the buildworlds.  No panics, but in the second set I
did have one buildworld (-j9) which failed with four processes
apparently getting a "*** Signal 6".  I am not sure what that
was about. Note that all these builds were done with a `make'
that was compiled to USE_KQUEUE , so maybe that's where the
Signal's came from.  In any case, the machine is still running
fine, even after that heavy pounding.

-- 
Garance Alistair Drosehn            =   gad at gilead.netel.rpi.edu
Senior Systems Programmer           or  gad at freebsd.org
Rensselaer Polytechnic Institute    or  drosih at rpi.edu