Re: [RFC patch 7/7] [PATCH] glibc: nptl: Add support for attached pthread_mutexes

[Thomas Gleixner]

On Sat, 2 Apr 2016, Peter Zijlstra wrote:
> On Sat, Apr 02, 2016 at 11:09:20AM -0000, Thomas Gleixner wrote:
> > To undo the attachment each involved thread needs to call
> > 
> >     pthread_mutex_detach_np(&mutex);
> >         
> > When the last user detaches the kernel state is destroyed.
> 
> So I was fully expecting pthread_mutex_{at,de}tach_np() to not exist and
> be internal to pthread_mutex_{init,destroy}().
> 
> Is there a reason this is not so?

init/destroy are only called once and not on all threads using the futex. If
you want to hide that, then you need to add it to all pthread_mutex_*
operations and attach on the first call.

That's possible, but for simplicity we made it explicit.

Thanks,

	tglx