[parisc-linux] Mysterious hangs with parisc

[Kyle McMartin]

On Fri, Jun 23, 2006 at 10:41:09PM -0400, John David Anglin wrote:
> This is not to say that the locking code can't be improved.  As far
> as I can tell, hpux doesn't spin.  It has pre-abitration, priorities
> for waiters, etc.  When a lock is released, suwaiters is called to
> pass the lock in a fair way to another waiter if there is one.
> 

HPUX spinlocks /do/ spin, afaict. They just keep track of how long
they've been spinning for (and panic after 60 seconds.) On release of
a spinlock, they also donate it to another cpu, which is, I guess, the
arbitration thing. I can back this up with disassembly, but I wouldn't
be comfortable doing it over mail, due to copyright infringement and
blah blah.

Cheers,
	 Kyle M.