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

Linus Torvalds
2009-01-07T16:27:00Z

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