[Development] QBasicMutex::lockInternal() race condition?

[Tony Van Eerd]

I have no solutions (yet?).  I just want to know how to constrain my thinking.  I basically won't even try going down the DCAS road.
Nor the LL/SC road, since C++11 has basically shunned that idea, sadly.

Solutions that map to C++11 concepts, with single-sized atomics, would probably be best.  Like what is there now. 

> -----Original Message-----
> From: development-bounces+tvaneerd=rim.com at qt-project.org
> [mailto:development-bounces+tvaneerd=rim.com at qt-project.org] On Behalf
> Of Thiago Macieira
> Sent: Friday, September 21, 2012 1:32 PM
> To: development at qt-project.org
> Subject: Re: [Development] QBasicMutex::lockInternal() race condition?
> 
> On sexta-feira, 21 de setembro de 2012 16.46.44, Tony Van Eerd wrote:
> > I'll take that as a 'No'.  ie use of DCAS would be limited to the
> point of
> > it not being worth maintaining 2 separate implementations - one with
> DCAS,
> > one without.  I think DCAS is only worth using if it could be used
> > everywhere.
> 
> Right. Because of the silly x86-64 early mistake, we need to support a
> non-
> DCAS version. Or ban those early processors without "cx16" support.
> 
> Even then, we need a separate implementation for LL/SC architectures.
> 
> We don't need to decide on that now. But if you do have a good solution
> with
> DCAS, we could consider it later. We just need to double the size of
> QMutex
> now.
> 
> --
> Thiago Macieira - thiago.macieira (AT) intel.com
>   Software Architect - Intel Open Source Technology Center
>      Intel Sweden AB - Registration Number: 556189-6027
>      Knarrarnäsgatan 15, 164 40 Kista, Stockholm, Sweden

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