Re: [PATCH -v5][RFC]: mutex: implement adaptive spinning

Linus Torvalds
2009-01-07T23:32:11Z

On Wed, 7 Jan 2009, Steven Rostedt wrote:
>
> What would be interesting is various benchmarks against all three.
>
> 1) no mutex spinning.
> 2) get_task_struct() implementation.
> 3) spin_or_sched implementation.

One of the issues is that I cannot convince myself that (2) is even
necessarily correct. At least not without having all cases happen inder
the mutex spinlock - which they don't. Even with the original patch, the
uncontended cases set and cleared the owner field outside the lock.

Linus