Re: membar_datadep_consumer

[Mindaugas Rasiukevicius <rmind%netbsd.org@localhost>]

Taylor R Campbell <campbell+netbsd-tech-kern%mumble.net@localhost> wrote:
> Any objections to introducing membar_datadep_consumer?
> 
> Semantics:  Any load afterward with a data dependency on a load
> beforehand is guaranteed to be ordered so.  Control dependencies are
> not ordered.
> 
> Implementation:  mb on Alpha, noop everywhere else for now.  Define
> __HAVE_MEMBAR_DATADEP_CONSUMER in XYZ/types.h if XYZ has it; otherwise
> <sys/atomic.h> automatically defines it as a noop.
> 
> I have been sitting on the attached patch for ages and plan to
> introduce its use where appropriate when I have time, with testing on
> a multiprocessor Alpha known to reorder data-dependent loads.

Seems fine to me.  Good luck ensuring its correct use, though. :)

-- 
Mindaugas