Re: [PATCH -v7][RFC]: mutex: implement adaptive spinning

[Steven Rostedt]

On Thu, 8 Jan 2009, Chris Mason wrote:
> On Thu, 2009-01-08 at 13:14 -0500, Steven Rostedt wrote:
> > 
> > If it was the current process that preempted the owner and these are RT 
> > tasks pinned to the same CPU and the owner is of lower priority than the 
> > spinner, we have a deadlock!
> > 
> > Hmm, I do not think the need_sched here will even fix that :-/
> 
> RT tasks could go directly to sleeping.  The spinner would see them on
> the list and break out.

True, we could do:

	if (owner) {
		if (!spin_on_owner(lock, owner))	
			break;
	} else if (rt_task(current))
		break;

That would at least solve the issue in the short term.

-- Steve
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