Re: [PATCH -v4][RFC]: mutex: implement adaptive spinning

[Linus Torvalds]

On Wed, 7 Jan 2009, Peter Zijlstra wrote:
>
> Change mutex contention behaviour such that it will sometimes busy wait on
> acquisition - moving its behaviour closer to that of spinlocks.

Ok, this one looks _almost_ ok.

The only problem is that I think you've lost the UP case. 

In UP, you shouldn't have the code to spin, and the "spin_or_schedule()" 
should fall back to just the schedule case.

It migth also be worthwhile to try to not set the owner, and re-organize 
that a bit (by making it a inline function that sets the owner only for 
CONFIG_SMP or lockdep/debug). 

			Linus
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