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

Peter W. Morreale
2009-01-07T23:17:51Z

On Wed, 2009-01-07 at 15:51 -0700, Peter W. Morreale wrote:
> On Wed, 2009-01-07 at 23:33 +0100, Ingo Molnar wrote:
> > * Gregory Haskins <ghaskins@novell.com> wrote:
> >
> > > Can I ask a simple question in light of all this discussion?
> > >
> > > "Is get_task_struct() really that bad?"
> >
> > it dirties a cacheline and it also involves atomics.
> >
> > Also, it's a small design cleanliness issue to me: get_task_struct()
> > impacts the lifetime of an object - and if a locking primitive has
> > side-effects on object lifetimes that's never nice.
> >
>
> True, but it's for one iteration * NR_CPUS, max.
>
> Best,
> -PWM

Never mind. Bogus argument.

That's why we have you Big Guns out there... - To keep us rif-raf in
line...

:-)

Best,
-PWM